Merge branch 'master' into remove-is_utc

5 files changed, 1487 insertions, 40 deletions

diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index ac52f39c..596ad989 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -11,6 +11,12 @@ macro(_join_list _var _sep)
 endmacro()
 
 find_package(Doxygen)
+set_package_properties(Doxygen PROPERTIES
+  TYPE OPTIONAL
+  DESCRIPTION "API Documentation system"
+  URL "http://www.doxygen.org"
+  PURPOSE "Needed to build the API documention."
+)
 if(DOXYGEN_FOUND)
   file(GLOB _dox_deps *.dox *.html)
   file(GLOB _all_hdrs
diff --git a/doc/Mainpage.dox b/doc/Mainpage.dox
index d9fed2bf..8a13de47 100644
--- a/doc/Mainpage.dox
+++ b/doc/Mainpage.dox
@@ -6,15 +6,15 @@
 Libical is an Open Source implementation of the iCalendar protocols
 and protocol data units. The iCalendar specification describes how
 calendar clients can communicate with calendar servers so users can
-store their calendar data and arrange meetings with other users. 
+store their calendar data and arrange meetings with other users.
 
 Libical implements RFC2445, RFC2446 and some of RFC2447.
 
 @section license License
 
 The code and datafiles in this distribution are licensed under the
-Mozilla Public License (MPL) v1.0. See http://www.mozilla.org/MPL/1.0
-for a copy of the license. 
+Mozilla Public License (MPL) v2.0. See http://www.mozilla.org/MPL
+for a copy of the license.
 
 Alternately, you may use libical under the terms of the GNU Library
 General Public License (LGPL) v2.1. See http://www.gnu.org/licenses/lgpl-2.1.txt
diff --git a/doc/UsingLibical.md b/doc/UsingLibical.md
new file mode 100644
index 00000000..5ef6457f
--- /dev/null
+++ b/doc/UsingLibical.md
@@ -0,0 +1,1441 @@
+# Using Libical
+
+>   Author: Eric Busboom <eric@softwarestudio.org>
+>   
+>   Date: January 2001
+
+## 1 Introduction
+
+Libical is an Open Source implementation of the iCalendar protocols
+and protocol data units. The iCalendar specification describes how
+calendar clients can communicate with calendar servers so users can
+store their calendar data and arrange meetings with other users.
+
+Libical implements [RFC5545][], [RFC5546][], [RFC7529][]; the 
+iCalendar extensions in [RFC6638][]; and some of [RFC6047][].
+
+
+This documentation assumes that you are familiar with the iCalendar
+standards RFC5545 and RFC5546. These specifications are available
+at the [IETF Tools][] website:
+
+[RFC5545]: https://tools.ietf.org/html/rfc5545
+[RFC5546]: https://tools.ietf.org/html/rfc5546
+[RFC7529]: https://tools.ietf.org/html/rfc7529
+[RFC6638]: https://tools.ietf.org/html/rfc6638
+[RFC6047]: https://tools.ietf.org/html/rfc6047
+[IETF Tools]: https://tools.ietf.org/
+
+### 1.1 The libical project
+
+This code is under active development. If you would like to contribute
+to the project, visit <http://libical.github.io/libical/>
+
+### 1.2 License
+
+The code and datafiles in this distribution are licensed under the
+Mozilla Public License version 2.0. See <http://www.mozilla.org/MPL>
+for a copy of the license. Alternately, you may use libical under
+the terms of the GNU Lesser General Public License, version 2.1.
+See <http://www.gnu.org/licenses/lgpl-2.1.html> for a copy of the LGPL.
+
+This dual license ensures that the library can be incorporated into
+both proprietary code and GPL'd programs, and will benefit from improvements
+made by programmers in both realms. I will only accept changes into
+my version of the library if they are similarly dual-licensed.
+
+### 1.3 Example Code
+
+A lot of the documentation for this library is in the form of example
+code. These examples are in the `examples/` directory of the distribution.
+Also look in `src/test/` for additional annotated examples.
+
+## 2 Building the Library
+
+Libical uses autoconf to generate makefiles. It should build with no
+adjustments on Linux, FreeBSD and Solaris under `gcc`. Some versions
+have been successfully built on MacOS, Solaris, UnixWare, And
+Tru64 UNIX without `gcc`, but you may run into problems with a particular
+later version.
+
+For a more complete guide to building the library, see the `README` file
+in the distribution.
+
+## 3 Structure
+
+The iCalendar data model is based on four types of objects: *components*,
+*properties*, *values* and *parameters*.
+
+Properties are the fundamental unit of information in iCalendar, and they
+work a bit like a hash entry, with a constant key and a variable value.
+Properties may also have modifiers, called parameters. In the iCal
+content line
+
+```ical
+ORGANIZER;ROLE=CHAIR:MAILTO:mrbig@host.com
+```
+
+The property name is `ORGANIZER`, the value of the property is `mrbig@host.com`
+and the `ROLE` parameter specifies that Mr Big is the chair of the
+meetings associated with this property.
+
+Components are groups of properties that represent the core objects
+of a calendar system, such as events or timezones. Components are
+delimited by `BEGIN` and `END` tags.
+
+When a component is sent across a network, if it is un-encrypted, it
+will look something like:
+
+```ical
+BEGIN:VCALENDAR
+METHOD:REQUEST
+PRODID: -//hacksw/handcal//NONSGML v1.0//EN
+BEGIN:VEVENT
+DTSTAMP:19980309T231000Z
+UID:guid-1.host1.com
+ORGANIZER;ROLE=CHAIR:MAILTO:mrbig@host.com
+ATTENDEE;RSVP=TRUE;ROLE=REQ-PARTICIPANT;CUTYPE=GROUP:
+  MAILTO:employee-A@host.com
+DESCRIPTION:Project XYZ Review Meeting
+CATEGORIES:MEETING
+CLASS:PUBLIC
+CREATED:19980309T130000Z
+SUMMARY:XYZ Project Review
+DTSTART;TZID=US-Eastern:19980312T083000
+DTEND;TZID=US-Eastern:19980312T093000
+LOCATION:1CP Conference Room 4350
+END:VEVENT
+END:VCALENDAR
+```
+
+Note that components can be nested; this example has both a VCALENDAR
+and a VEVENT component, one nested inside the other.
+
+### 3.1 Core iCal classes
+
+Libical is an object-based, data-oriented library. Nearly all of the
+routines in the library are associated with an opaque data types and
+perform some operation on that data type. Although the library does
+not actually have classes, we will use those terms since the behavior
+of these associations of data and routines is very similar to a class.
+
+#### 3.1.1 Properties
+
+Properties are represented with the `icalproperty` class and its many
+"derived" classes with one "derived" class per property type in [RFC5545][].
+Again, there is no actual inheritance relations, but there are clusters
+of routines that make this term useful. A property is a container
+for a single value and a set of parameters.
+
+#### 3.1.2 Components
+
+In libical, components are represented with the `icalcomponent` class.
+`icalcomponent` is a container for a set of other components and properties.
+
+#### 3.1.3 Values
+
+Values are represented in a similar way to properties; a base class
+and many "derived " classes. A value is essentially a abstract handle
+on a single fundamental type, a structure or a union.
+
+#### 3.1.4 Parameters
+
+Parameters are represented in a similar way to properties, except that
+they contain only one value.
+
+### 3.2 Other elements of libical
+
+In addition to the core iCal classes, libical has many other types,
+structures, and classes that aid in creating and using iCal components.
+
+#### 3.2.1 Enumerations and types
+
+Libical is strongly typed, so every component, property, parameter,
+and value type has an enumeration, and some have an associated structure
+or union.
+
+#### 3.2.2 The parser
+
+The libical parser offers a variety of ways to convert [RFC5545][] text 
+into a libical internal component structure. The parser can parse
+blocks of text as a string, or it can parse line-by-line.
+
+#### 3.2.3 Error objects
+
+Libical has a substantial error reporting system for both programming
+errors and component usage errors.
+
+#### 3.2.4 Memory Management
+
+Since many of libicals interfaces return strings, the library has its
+own memory management system to elimiate the need to free every string
+returned from the library.
+
+#### 3.2.5 Storage classes
+
+The library also offers several classes to store components to files,
+memory or databases.
+
+## 4 Differences From RFCs
+
+Libical has been designed to follow the standards as closely as possible,
+so that the key objects in the standards are also key objects in the
+library. However, there are a few areas where the specifications are
+(arguably) irregular, and following them exactly would result in an
+unfriendly interface. These deviations make libical easier to use
+by maintaining a self-similar interface.
+
+### 4.1 Pseudo Components
+
+Libical defines components for groups of properties that look and act
+like components, but are not defined as components in the specification.
+`XDAYLIGHT` and `XSTANDARD` are notable examples. These pseudo components
+group properties within the `VTIMEZONE` components. For instanace, the
+timezone properties associated with daylight savings time starts with
+`BEGIN:DAYLIGHT` and ends with `END:DAYLIGHT`, just like other components,
+but is not defined as a component in [RFC5545][] (see [section 3.6.5][RFC5545 3.6.5])
+In libical, this grouping is represented by the `XDAYLIGHT` component.
+Standard iCal components all start with the letter "V," while pseudo
+components start with "X."
+
+There are also pseudo components that are conceptually derived classes
+of `VALARM`. [RFC5546][] defines what properties may be included in each
+component, and for `VALARM`, the set of properties it may have depends
+on the value of the `ACTION` property.
+
+For instance, if a `VALARM` component has an `ACTION` property with the
+value of `AUDIO`, the component must also have an `ATTACH` property.
+However, if the `ACTION` value is `DISPLAY`, the component must have
+a `DESCRIPTION` property.
+
+To handle these various, complex restrictions, libical has pseudo components
+for each type of alarm: `XAUDIOALARM`, `XDISPLAYALARM`, `XEMAILALARM` and
+`XPROCEDUREALARM`.
+
+[RFC5545 3.6.5]: <https://tools.ietf.org/html/rfc5545#section-3.6.5>
+
+### 4.2 Combined Values
+
+Many values can take more than one type. `TRIGGER`, for instance, can
+have a value type of with `DURATION` or of `DATE-TIME`. These multiple
+types make it difficult to create routines to return the value associated
+with a property.
+
+It is natural to have interfaces that would return the value of a property,
+but it is cumbersome for a single routine to return multiple types.
+So, in libical, properties that can have multiple types are given
+a single type that is the union of their RFC5545 types. For instance,
+in libical, the value of the `TRIGGER` property resolves to struct 
+`icaltriggertype`. This type is a union of a `DURATION` and a `DATE-TIME`.
+
+### 4.3 Multi-Valued Properties
+
+Some properties, such as `CATEGORIES` have only one value type, but each
+`CATEGORIES` property can have multiple value instances. This also results
+in a cumbersome interface -- `CATEGORIES` accessors would have to return
+a list while all other accessors returned a single value. In libical,
+all properties have a single value, and multi-valued properties are
+broken down into multiple single valued properties during parsing.
+That is, an input line like,
+
+```ical
+CATEGORIES: work, home
+```
+
+becomes in libical's internal representation
+
+```ical
+CATEGORIES: work
+CATEGORIES: home
+```
+
+Oddly, [RFC5545][] allows some multi-valued properties (like `FREEBUSY`)
+to exist as both a multi-values property and as multiple single
+value properties, while others (like `CATEGORIES`) can only exist
+as single multi-valued properties. This makes the internal representation
+for `CATEGORIES` illegal.  However when you convert a component to a
+string, the library will collect all of the `CATEGORIES` properties
+into one.
+
+## 5 Using libical
+
+### 5.1 Creating Components
+
+There are three ways to create components in Libical: 
+1.  creating individual objects and assembling them, 
+2.  building entire objects in massive vaargs calls, 
+3.  and parsing a text file containing iCalendar data.
+
+#### 5.1.1 Constructor Interfaces
+
+Using constructor interfaces, you create each of the objects separately
+and then assemble them in to components:
+
+```c
+icalcomponent *event;
+icalproperty *prop;
+icalparameter *param;
+struct icaltimetype atime;
+
+// create new VEVENT component
+event = icalcomponent_new(ICAL_VEVENT_COMPONENT);
+
+// add DTSTAMP property to the event
+prop = icalproperty_new_dtstamp(atime);
+icalcomponent_add_property(event, prop);
+
+// add UID property to the event
+prop = icalproperty_new_uid("guid-1.example.com");
+icalcomponent_add_property(event, prop);
+
+// add ORGANIZER (with ROLE=CHAIR) to the event
+prop = icalproperty_new_organizer("mrbig@example.com");
+param = icalparameter_new_role(ICAL_ROLE_CHAIR);
+icalproperty_add_parameter(prop, param);
+icalcomponent_add_property(event, prop);
+```
+
+Notice that libical uses a semi-object-oriented style of interface.
+Most things you work with are objects, that are instantiated with
+a constructor that has "new" in the name. Also note that, other than
+the object reference, most structure data is passed in to libical
+routines by value. Libical has some complex but very regular memory
+handling rules. These are detailed in section [sec:memory].
+
+If any of the constructors fail, they will return 0. If you try to
+insert 0 into a property or component, or use a zero-valued object
+reference, libical will either silently ignore the error or will abort
+with an error message. This behavior is controlled by a compile time
+flag (`ICAL_ERRORS_ARE_FATAL`), and will abort by default.
+
+#### 5.1.2 varargs Constructors
+
+There is another way to create complex components, which is arguably
+more elegant, if you are not horrified by varargs. The varargs constructor
+interface allows you to create intricate components in a single block
+of code. Here is the previous examples in the vaargs style.
+
+```c
+icalcomponent *calendar;
+struct icaltimetype atime;
+
+calendar =
+    icalcomponent_vanew(
+        ICAL_VCALENDAR_COMPONENT,
+        icalproperty_new_version("2.0"),
+        icalproperty_new_prodid(
+             "-//RDU Software//NONSGML HandCal//EN"),
+        icalcomponent_vanew(
+            ICAL_VEVENT_COMPONENT,
+            icalproperty_new_dtstamp(atime),
+            icalproperty_new_uid("guid-1.host1.com"),
+            icalproperty_vanew_organizer(
+                "mrbig@host.com",
+                icalparameter_new_role(ICAL_ROLE_CHAIR),
+                NULL),
+            icalproperty_vanew_attendee(
+                "employee-A@host.com",
+                icalparameter_new_role(
+                    ICAL_ROLE_REQPARTICIPANT),
+                icalparameter_new_rsvp(1),
+                icalparameter_new_cutype(ICAL_CUTYPE_GROUP),
+                NULL),
+            icalproperty_new_location(
+               "1CP Conference Room 4350"),
+            NULL),
+        NULL);
+```
+
+This form is similar to the constructor form, except that the constructors
+have `vanew` instead of `new` in the name. The arguments are similar
+too, except that the component constructor can have a list of properties,
+and the property constructor can have a list of parameters. 
+
+*Be sure to terminate every list with a `NULL` (or a *`(void 0)`*, or your code 
+will crash, if you are lucky*. The reason you can't use 0 itself is that
+depending on what platform you are on, `sizeof(int) ≠ sizeof(void*)`.
+
+#### 5.1.3 Parsing Text Files
+
+The final way to create components will probably be the most common;
+you can create components from [RFC5545][] compliant text. If you have
+the string in memory, use
+
+```c
+icalcomponent* icalparser_parse_string(char* str);
+```
+
+If the string contains only one component, the parser will return the
+component in libical form. If the string contains multiple components,
+the multiple components will be returned as the children of an 
+`ICAL_XROOT_COMPONENT` component.
+
+Parsing a whole string may seem wasteful if you want to pull a large
+component off of the network or from a file; you may prefer to parse
+the component line by line. This is possible too by using:
+
+```c
+icalparser* icalparser_new();
+
+void icalparser_free(
+    icalparser* parser);
+
+icalparser_get_line(
+    icalparser *parser,
+    char* (*read_stream)(char *s, size_t size,  void* d));
+
+icalparser_add_line(
+    icalparser *parser,
+    char *line);
+
+icalparser_set_gen_data(
+    icalparser *parser,
+    void *data);
+```
+
+These routines will construct a parser object to which you can add
+lines of input and retrieve any components that the parser creates
+from the input. These routines work by specifing an adaptor routine
+to get string data from a source. For example:
+
+```c
+char* read_stream(char *s, size_t size, void *d)
+{
+    return fgets(s, size, (FILE*)d);
+}
+
+int main(int argc, char *argv[]) 
+{
+    char *line;
+    icalcomponent *component;
+    icalparser *parser = icalparser_new();
+
+    // open file (first command-line argument)
+    FILE* stream = fopen(argv[1], "r");
+
+    // associate the FILE with the parser so that read_stream
+    // will have access to it
+    icalparser_set_gen_data(parser, stream);
+
+    do {
+        // read the file, line-by-line, and parse the data
+        line = icalparser_get_line(parser, read_stream);
+        component = icalparser_add_line(parser, line);
+
+        // if icalparser has finished parsing a component,
+        // it will return it
+        if (component != 0) {
+            // print the parsed component
+            printf("%s", icalcomponent_as_ical_string(component));
+            icalparser_clean(parser);
+
+            printf("\n---------------\n");
+
+            icalcomponent_free(component);
+        }
+    } while (line != 0);
+
+    return 0;
+}
+```
+
+The parser object parameterizes the routine used to get input lines
+with `icalparser_set_gen_data()`and `icalparser_get_line()`. In this
+example, the routine `read_stream()` will fetch the next line from a
+stream, with the stream passed in as the `void*` parameter d. The parser
+calls `read_stream()` from `icalparser_get_line()`, but it also needs
+to know what stream to use. This is set by the call to `icalparser_set_gen_data()`.
+By using a different routine for `read_stream()` or passing in different
+data with `icalparser_set_gen_data()`, you can connect to any data source.
+
+Using the same mechanism, other implementations could read from memory
+buffers, sockets or other interfaces.
+
+Since the example code is a very common way to use the parser, there
+is a convenience routine;
+
+```c
+icalcomponent* icalparser_parse(
+    icalparser *parser,
+    char* (*line_gen_func)(char *s, size_t size,  void* d));
+```
+
+To use this routine, you still must construct the parser object and
+pass in a reference to a line reading routine. If the parser can create
+a single component from the input, it will return a pointer to the
+newly constructed component. If the parser can construct multiple
+components from the input, it will return a reference to an `XROOT`
+component (of type `ICAL_XROOT_COMPONENT`.) This `XROOT` component will
+hold all of the components constructed from the input as children.
+
+```c
+char* read_stream(char *s, size_t size, void *d)
+{
+    return fgets(s, size, (FILE*)d);
+}
+
+int main(int argc, char *argv[]) 
+{
+    char* line;
+    icalcomponent *component;
+    icalparser *parser = icalparser_new();
+
+    // open file (first command-line argument)
+    FILE* stream = fopen(argv[1], "r");
+
+    // associate the FILE with the parser so that read_stream
+    // will have access to it
+    icalparser_set_gen_data(parser, stream);
+
+    // parse the opened file
+    component = icalparser_parse(parser, read_stream);
+
+    if (component != 0) {
+        // print the parsed component
+        printf("%s", icalcomponent_as_ical_string(component));
+        icalcomponent_free(component);
+    }
+
+    icalparser_free(parser);
+
+    return 0;
+}
+```
+
+### 5.2 Accessing Components
+
+Given a reference to a component, you probably will want to access
+the properties, parameters and values inside. Libical interfaces let
+you find sub-component, add and remove sub-components, and do the
+same three operations on properties.
+
+#### 5.2.1 Finding Components
+
+To find a sub-component of a component, use:
+
+```c
+icalcomponent* icalcomponent_get_first_component(
+    icalcomponent* component,
+    icalcomponent_kind kind);
+```
+
+This routine will return a reference to the first component of the
+type `kind`. The key kind values, listed in icalenums.h are:
+
+-   `ICAL_ANY_COMPONENT`
+-   `ICAL_VEVENT_COMPONENT`
+-   `ICAL_VTODO_COMPONENT`
+-   `ICAL_VJOURNAL_COMPONENT`
+-   `ICAL_VCALENDAR_COMPONENT`
+-   `ICAL_VFREEBUSY_COMPONENT`
+-   `ICAL_VALARM_COMPONENT`
+
+These are only the most common components; there are many more listed
+in icalenums.h.
+
+As you might guess, if there is more than one subcomponent of the type
+you have chosen, this routine will return only the first. to get at
+the others, you need to iterate through the component.
+
+#### 5.2.2 Iterating Through Components
+
+Iteration requires a second routine to get the next subcomponent after
+the first:
+
+```c
+icalcomponent* icalcomponent_get_next_component(
+    icalcomponent* component,
+    icalcomponent_kind kind);
+```
+
+With the 'first' and 'next' routines, you can create a for loop to
+iterate through all of a components subcomponents
+
+```c
+icalcomponent *c;
+
+for(c = icalcomponent_get_first_component(comp, ICAL_ANY_COMPONENT);
+    c != 0;
+    c = icalcomponent_get_next_component(comp, ICAL_ANY_COMPONENT))
+{
+      do_something(c);
+}
+```
+
+This code bit wil iterate through all of the subcomponents in `comp`
+but you can select a specific type of component by changing `ICAL_ANY_COMPONENT`
+to another component type.
+
+#### 5.2.3 Using Component Iterators
+
+The iteration model in the previous section requires the component
+to keep the state of the iteration. So, you could not use this model
+to perform a sorting operations, since you'd need two iterators and
+there is only space for one. If you ever call `icalcomponent_get_first_component()`
+when an iteration is in progress, the pointer will be reset to the
+beginning.
+
+To solve this problem, there are also external iterators for components.
+The routines associated with these external iterators are:
+
+```c
+icalcompiter icalcomponent_begin_component(
+    icalcomponent* component,
+    icalcomponent_kind kind);
+
+icalcompiter icalcomponent_end_component(
+    icalcomponent* component,
+    icalcomponent_kind kind);
+
+icalcomponent* icalcompiter_next(
+    icalcompiter* i);
+
+icalcomponent* icalcompiter_prior(
+    icalcompiter* i);
+
+icalcomponent* icalcompiter_deref(
+    icalcompiter* i);
+```
+
+The `*_begin_*()` and `*_end_*()` routines return a new iterator that points
+to the beginning and end of the list of subcomponent for the given
+component, and the kind argument works like the kind argument for
+internal iterators.
+
+After creating an iterators, use `*_next()` and `*_prior()` to step forward
+and backward through the list and get the component that the iterator
+points to, and use `_deref()` to return the component that the iterator
+points to without moving the iterator. All routines will return 0
+when they move to point off the end of the list.
+
+Here is an example of a loop using these routines:
+
+```c
+for(i = icalcomponent_begin_component(impl->cluster, ICAL_ANY_COMPONENT);
+    icalcompiter_deref(&i)!= 0;
+    icalcompiter_next(&i)) 
+{
+    icalcomponent *this = icalcompiter_deref(&i);
+}
+```
+
+#### 5.2.4 Removing Components
+
+Removing an element from a list while iterating through the list with
+the internal iterators can cause problems, since you will probably
+be removing the element that the internal iterator points to. The
+`_remove()` routine will keep the iterator valid by moving it to the
+next component, but in a normal loop, this will result in two advances
+per iteration, and you will remove only every other component.  To
+avoid the problem, you will need to step the iterator ahead of the
+element you are going to remove, like this:
+
+```c
+for(c = icalcomponent_get_first_component(parent_comp, ICAL_ANY_COMPONENT);
+    c != 0;
+    c = next)
+{
+    next = icalcomponent_get_next_component(parent_comp, ICAL_ANY_COMPONENT);
+    icalcomponent_remove_component(parent_comp,c);
+}
+```
+
+Another way to remove components is to rely on the side effect of 
+`icalcomponent_remove_component()`:
+if component iterator in the parent component is pointing to the child
+that will be removed, it will move the iterator to the component after
+the child. The following code will exploit this behavior:
+
+```c
+icalcomponent_get_first_component(parent_comp,ICAL_VEVENT_COMPONENT);
+
+while((c=icalcomponent_get_current_component(c)) != 0){
+   if(icalcomponent_isa(c) == ICAL_VEVENT_COMPONENT){
+      icalcomponent_remove_component(parent_comp,inner);
+   } else {
+      icalcomponent_get_next_component(parent_comp,ICAL_VEVENT_COMPONENT);
+   }
+}
+```
+
+#### 5.2.5 Working with properties and parameters
+
+Finding, iterating and removing properties works the same as it does
+for components, using the property-specific or parameter-specific
+interfaces:
+
+```c
+icalproperty* icalcomponent_get_first_property(
+    icalcomponent* component,
+    icalproperty_kind kind);
+
+icalproperty* icalcomponent_get_next_property(
+    icalcomponent* component,
+    icalproperty_kind kind);
+
+void icalcomponent_add_property(
+    icalcomponent* component,
+    icalproperty* property);
+
+void icalcomponent_remove_property(
+    icalcomponent* component,
+    icalproperty* property);
+```
+
+For parameters:
+
+```c
+icalparameter* icalproperty_get_first_parameter(
+     icalproperty* prop,
+     icalparameter_kind kind);
+
+icalparameter* icalproperty_get_next_parameter(
+     icalproperty* prop,
+     icalparameter_kind kind);
+
+void icalproperty_add_parameter(
+     icalproperty* prop,
+     icalparameter* parameter);
+
+void icalproperty_remove_parameter_by_kind(
+     icalproperty* prop,
+     icalparameter_kind kind);
+```
+
+Note that since there should be only one parameter of each type in
+a property, you will rarely need to use `icalparameter_get_next_parameter()`.
+
+#### 5.2.6 Working with values
+
+Values are typically part of a property, although they can exist on
+their own. You can manipulate them either as part of the property
+or independently.
+
+The most common way to work with values to is to manipulate them from
+they properties that contain them. This involves fewer routine calls
+and intermediate variables than working with them independently, and
+it is type-safe.
+
+For each property, there are a `_get_()` and a `_set_()` routine that 
+accesses the internal value. For instanace, for the `UID` property, the 
+routines are:
+
+```c
+void icalproperty_set_uid(
+    icalproperty* prop, 
+    const char* v);
+
+const char* icalproperty_get_uid(
+    icalproperty* prop);
+```
+
+For multi-valued properties, like `ATTACH`, the value type is usually
+a struct or union that holds both possible types.
+
+If you want to work with the underlying value object, you can get and
+set it with:
+
+```c
+icalvalue* icalproperty_get_value(
+    icalproperty* prop);
+
+void icalproperty_set_value(
+    icalproperty* prop, 
+    icalvalue* value);
+```
+
+`icalproperty_get_value()` will return a reference that you can manipulate
+with other icalvalue routines. Most of the time, you will have to
+know what the type of the value is. For instance, if you know that
+the value is a `DATETIME` type, you can manipulate it with:
+
+```c
+struct icaltimetype icalvalue_get_datetime(
+    icalvalue* value);
+
+void icalvalue_set_datetime(
+    icalvalue* value, 
+    struct icaltimetype v);
+```
+
+When working with an extension property or value (and `X-PROPERTY` or
+a property that has the parameter `VALUE=x-name`), the value type is
+always a string. To get and set the value, use:
+
+```x
+void icalproperty_set_x(
+    icalproperty* prop, 
+    char* v);
+
+char* icalproperty_get_x(
+    icalproperty* prop);
+```
+
+All X properties have the type of `ICAL_X_PROPERTY`, so you will need
+these routines to get and set the name of the property:
+
+```c
+char* icalproperty_get_x_name(
+    icalproperty* prop)
+
+void icalproperty_set_x_name(
+    icalproperty* prop, 
+    char* name);
+```
+
+#### 5.2.7 Checking Component Validity
+
+[RFC5546][] defines rules for what properties must exist in a component
+to be used for transferring scheduling data. Most of these rules relate
+to the existence of properties relative to the `METHOD` property, which
+declares what operation a remote receiver should use to process a
+component. For instance, if the `METHOD` is `REQUEST` and the component
+is a `VEVENT`, the sender is probably asking the receiver to join in
+a meeting. In this case, RFC5546 says that the component must specify
+a start time (`DTSTART`) and list the receiver as an attendee 
+(`ATTENDEE`).
+
+Libical can check these restrictions with the routine:
+
+```c
+int icalrestriction_check(icalcomponent* comp);
+```
+
+This routine returns 0 if the component does not pass RFC5546 restrictions,
+or if the component is malformed. The component you pass in must be
+a `VCALENDAR`, with one or more children, like the examples in RFC5546.
+
+When this routine runs, it will insert new properties into the component
+to indicate any errors it finds. See section 6.5.3, `X-LIC-ERROR` for
+more information about these error properties.
+
+5.2.8 Converting Components to Text
+
+To create an RFC5545 compliant text representation of an object, use
+one of the `*_as_ical_string()` routines:
+
+```c
+char* icalcomponent_as_ical_string(icalcomponent* component)
+
+char* icalproperty_as_ical_string(icalproperty* property)
+
+char* icalparameter_as_ical_string(icalparameter* parameter)
+
+char* icalvalue_as_ical_string(icalvalue* value)
+```
+
+In most cases, you will only use `icalcomponent_as_ical_string()`, since
+it will cascade and convert all of the parameters, properties and
+values that are attached to the root component.
+
+Remember that the string returned by these routines is owned by the
+library, and will eventually be re-written. You should copy it if
+you want to preserve it.
+
+### 5.3 Time
+
+#### 5.3.1 Time structure
+
+Libical defines its own time structure for storing all dates and times.
+It would have been nice to re-use the C library's struct `tm`, but that
+structure does not differentiate between dates and times, and between
+local time and UTC. The libical structure is:
+
+```c
+struct icaltimetype {
+  int year;
+  int month;
+  int day;
+  int hour;
+  int minute;
+  int second;
+  int is_utc; /* 1-> time is in UTC timezone */
+  int is_date; /* 1 -> interpret this as date. */ 
+};
+```
+
+The `year`, `month`, `day`, `hour`, `minute` and `second` fields 
+hold the broken-out
+time values. The `is_utc` field distinguishes between times in UTC and
+a local time zone. The `is_date` field indicates if the time should
+be interpreted only as a date. If it is a date, the hour, minute and
+second fields are assumed to be zero, regardless of their actual vaules.
+
+#### 5.3.2 Creating time structures
+
+There are several ways to create a new icaltimetype structure:
+
+```c
+struct icaltimetype icaltime_from_string(
+    const char* str);
+
+struct icaltimetype icaltime_from_timet_with_zone(
+    time_t v,
+    int is_date,
+    icaltimezone* zone);
+```
+
+`icaltime_from_string()` takes any RFC5545 compliant time string:
+
+```c
+struct icaltimetype tt = icaltime_from_string("19970101T103000");
+```
+
+`icaltime_from_timet_with_zone()` takes a `time_t` value, representing seconds past
+the POSIX epoch, a flag to indicate if the time is a date, and a time zone.
+Dates have an identical structure to a time, but the time portion (hours,
+minuts and seconds) is always 00:00:00. Dates act differently in
+sorting and comparision, and they have a different string representation
+in [RFC5545][].
+
+#### 5.3.3 Time manipulating routines
+
+The `null` time value is used to indicate that the data in the structure
+is not a valid time.
+
+```c
+struct icaltimetype icaltime_null_time(void);
+
+int icaltime_is_null_time(struct icaltimetype t);
+```
+
+It is sensible for the broken-out time fields to contain values that
+are not permitted in an ISO compliant time string. For instance, the
+seconds field can hold values greater than 59, and the hours field
+can hold values larger than 24. The excessive values will be rolled
+over into the next larger field when the structure is normalized.
+
+```c
+struct icaltimetype icaltime_normalize(struct icaltimetype t);
+```
+
+Normalizing allows you to do arithmetic operations on time values.
+
+```c
+struct icaltimetype tt = icaltime_from_string("19970101T103000");
+
+tt.days +=3
+tt.second += 70;
+
+tt = icaltime_normalize(tt);
+```
+
+There are several routines to get the day of the week or month, etc,
+from a time structure.
+
+```c
+short icaltime_day_of_year(
+    struct icaltimetype t);
+
+struct icaltimetype icaltime_from_day_of_year(
+    short doy, 
+    short year);
+
+short icaltime_day_of_week(
+    struct icaltimetype t);
+
+short icaltime_start_doy_week(
+    struct icaltimetype t, 
+    int fdow);
+
+short icaltime_week_number(
+    short day_of_month, 
+    short month, 
+    short year);
+
+short icaltime_days_in_month(
+    short month,
+    short year);
+```
+
+Two routines convert time structures to and from the number of seconds
+since the POSIX epoch. The `is_date` field indicates whether or not
+the hour, minute and second fields should be used in the conversion.
+
+```c
+struct icaltimetype icaltime_from_timet_with_zone(
+    time_t v,
+    int is_date,
+    icaltimezone* zone);
+
+time_t icaltime_as_timet(
+    struct icaltimetype);
+```
+
+The compare routine works exactly like `strcmp()`, but on time structures.
+
+```c
+int icaltime_compare(
+    struct icaltimetype a, 
+    struct icaltimetype b);
+```
+
+The following routines convert between UTC and a named timezone. The
+tzid field must be a timezone name from the Olsen database, such as
+`America/Los_Angeles`.
+
+The `utc_offset` routine returns the offset of the named time zone from
+UTC, in seconds.
+
+The `tt` parameter in the following routines indicates the date on which
+the conversion should be made. The parameter is necessary because
+timezones have many different rules for when daylight savings time
+is used, and these rules can change over time. So, for a single timezone
+one year may have daylight savings time on March 15, but for other
+years March 15 may be standard time, and some years may have standard
+time all year.
+
+```c
+int icaltime_utc_offset(
+    struct icaltimetype tt, 
+    char* tzid);
+
+int icaltime_local_utc_offset();
+
+struct icaltimetype icaltime_as_utc(
+    struct icaltimetype tt, 
+    char* tzid);
+
+struct icaltimetype icaltime_as_zone(
+    struct icaltimetype tt, 
+    char* tzid);
+
+struct icaltimetype icaltime_as_local(
+    struct icaltimetype tt);
+```
+
+### 5.4 Storing Objects
+
+The libical distribution includes a separate library, libicalss, that
+allows you to store iCal component data to disk in a variety of ways.
+
+The file storage routines are organized in an inheritance heirarchy
+that is rooted in icalset, with the derived class icalfileset and
+icaldirset. Icalfileset stores components to a file, while icaldirset
+stores components to multiple files, one per month based on DTSTAMP.
+Other storages classess, for storage to a heap or a mysql database
+for example, could be added in the future.
+
+All of the icalset derived classes have the same interface:
+
+```c
+icaldirset* icaldirset_new(
+    const char* path);
+
+void icaldirset_free(
+    icaldirset* store);
+
+const char* icaldirset_path(
+    icaldirset* store);
+
+void icaldirset_mark(
+    icaldirset* store);
+
+icalerrorenum icaldirset_commit(
+    icaldirset* store);
+
+icalerrorenum icaldirset_add_component(
+    icaldirset* store, 
+    icalcomponent* comp);
+
+icalerrorenum icaldirset_remove_component(
+    icaldirset* store, 
+    icalcomponent* comp);
+
+int icaldirset_count_components(
+    icaldirset* store, 
+    icalcomponent_kind kind);
+
+icalerrorenum icaldirset_select(
+    icaldirset* store, 
+    icalcomponent* gauge);
+
+void icaldirset_clear(
+    icaldirset* store);
+
+icalcomponent* icaldirset_fetch(
+    icaldirset* store, 
+    const char* uid);
+
+int icaldirset_has_uid(
+    icaldirset* store, 
+    const char* uid);
+
+icalcomponent* icaldirset_fetch_match(
+    icaldirset* set, 
+    icalcomponent *c);
+
+icalerrorenum icaldirset_modify(
+    icaldirset* store, 
+    icalcomponent *oldc,
+    icalcomponent *newc);
+
+icalcomponent* icaldirset_get_current_component(
+    icaldirset* store);
+
+icalcomponent* icaldirset_get_first_component(
+    icaldirset* store);
+
+icalcomponent* icaldirset_get_next_component(
+    icaldirset* store);
+```
+
+#### 5.4.1 Creating a new set
+
+You can create a new set from either the base class or the direved
+class. From the base class use one of:
+
+```c
+icalset* icalset_new_file(const char* path);
+
+icalset* icalset_new_dir(const char* path);
+
+icalset* icalset_new_heap(void);
+
+icalset* icalset_new_mysql(const char* path);
+```
+
+You can also create a new set based on the derived class, For instance,
+with icalfileset:
+
+```c
+icalfileset* icalfileset_new(
+    const char* path);
+
+icalfileset* icalfileset_new_open(
+    const char* path, 
+    int flags, 
+    int mode);
+```
+
+`icalset_new_file()` is identical to `icalfileset_new()`. Both routines will
+open an existing file for readinga and writing, or create a new file
+if it does not exist. `icalfilset_new_open()` takes the same arguments
+as the open() system routine and behaves in the same way.
+
+The icalset and icalfilset objects are somewhat interchangable -- you
+can use an `icalfileset*` as an argument to any of the icalset routines.
+
+The following examples will all use icalfileset routines; using the
+other icalset derived classess will be similar.
+
+#### 5.4.2 Adding, Finding and Removing Components
+
+To add components to a set, use:
+
+```c
+icalerrorenum icalfileset_add_component(
+    icalfileset* cluster, 
+    icalcomponent* child);
+```
+
+The fileset keeps an inmemory copy of the components, and this set
+must be written back to the file ocassionally. There are two routines
+to manage this:
+
+```c
+void icalfileset_mark(icalfileset* cluster);
+
+icalerrorenum icalfileset_commit(icalfileset* cluster);
+```
+
+`icalfileset_mark()` indicates that the in-memory components have changed.
+Calling the `_add_component()` routine will call `_mark()` automatically,
+but you may need to call it yourself if you have made a change to
+an existing component. The `_commit()` routine writes the data base to
+disk, but only if it is marked. The `_commit()` routine is called automatically
+when the icalfileset is freed.
+
+To iterate through the components in a set, use:
+
+```c
+icalcomponent* icalfileset_get_first_component(icalfileset* cluster);
+
+icalcomponent* icalfileset_get_next_component(icalfileset* cluster);
+
+icalcomponent* icalfileset_get_current_component (icalfileset* cluster);
+```
+
+These routines work like the corresponding routines from icalcomponent,
+except that their output is filtered through a gauge. A gauge is a
+test for the properties within a components; only components that
+pass the test are returned. A gauge can be constructed from a MINSQL
+string with:
+
+```c
+icalgauge* icalgauge_new_from_sql(const char* sql);
+```
+
+Then, you can add the gauge to the set with :
+
+```c
+icalerrorenum icalfileset_select(
+    icalfileset* store, 
+    icalgauge* gauge);
+```
+
+Here is an example that puts all of these routines together:
+
+```c
+void test_fileset()
+{
+    icalfileset *fs;
+    icalcomponent *c;
+    int i;
+    char *path = "test_fileset.ics";
+
+    icalgauge  *g = icalgauge_new_from_sql(
+        "SELECT * FROM VEVENT WHERE DTSTART > '20000103T120000Z' AND
+DTSTART <= '20000106T120000Z'");
+
+    fs = icalfileset_new(path);
+
+    for (i = 0; i!= 10; i++){
+        c = make_component(i); /* Make a new component where DTSTART
+has month of i */
+        icalfileset_add_component(fs,c);
+    }
+
+    icalfileset_commit(fs); /* Write to disk */
+    icalfileset_select(fs,g); /* Set the gauge to filter components */
+
+    for (c = icalfileset_get_first_component(fs);
+         c != 0;
+         c = icalfileset_get_next_component(fs))
+    {
+        struct icaltimetype t = icalcomponent_get_dtstart(c);
+        printf("%s\n",icaltime_as_ctime(t));
+
+    }
+
+    icalfileset_free(fs);
+}
+```
+
+#### 5.4.3 Other routines
+
+There are several other routines in the icalset interface, but they
+not fully implemented yet.
+
+#### 5.5 Memory Management
+
+Libical relies heavily on dynamic allocation for both the core objects
+and for the strings used to hold values. Some of this memory the library
+caller owns and must free, and some of the memory is managed by the
+library. Here is a summary of the memory rules.
+
+1.  If the function name has "new" in it (such as `icalcomponent_new()`,
+    or `icalpropert_new_clone()`), the caller gets control
+    of the memory.
+
+2.  If you got the memory from a routine with new in it, you must
+    call the corresponding `*_free()` routine to free the memory, for
+    example use `icalcomponent_free()` to free objects created with 
+    `icalcomponent_new()`)
+
+3.  If the function name has "add" in it, the caller is transferring
+    control of the memory to the routine, for example the function
+    ` icalproperty_add_parameter()`
+
+4.  If the function name has "remove" in it, the caller passes in
+    a pointer to an object and after the call returns, the caller owns
+    the object. So, before you call `icalcomponent_remove_property(comp, foo)`,
+    you do not own "foo" and after the call returns, you do.
+
+5.  If the routine returns a string and its name does NOT end in `_r`,
+    libical owns the memory and will put it on a ring buffer to reclaim
+    later. For example, `icalcomponent_as_ical_string()`. You better
+    `strdup()` it if you want to keep it, and you don't have to delete it.
+
+6.  If the routine returns a string and its name *does* end in `_r`, the
+    caller gets control of the memory and is responsible for freeing it.
+    For example, `icalcomponent_as_ical_string_r()` does the same thing as
+    `icalcomponent_as_ical_string()`, except you now have control of the
+    string buffer it returns.
+
+### 5.6 Error Handling
+
+Libical has several error handling mechanisms for the various types
+of programming, semantic and syntactic errors you may encounter.
+
+#### 5.6.1 Return values
+
+Many library routines signal errors through their return values. All
+routines that return a pointer, such as `icalcomponent_new()`, will
+return 0 (zero) on a fatal error. Some routines will return a value
+of enum `icalerrorenum`.
+
+5.6.2 `icalerrno`
+
+Most routines will set the global error value `icalerrno` on errors.
+This variable is an enumeration; permissible values can be found in
+`libical/icalerror.h`. If the routine returns an enum icalerrorenum,
+then the return value will be the same as icalerrno. You can use 
+`icalerror_strerror()` to get a string that describes the error. 
+The enumerations are:
+
+-   `ICAL_BADARG_ERROR`: One of the argument to a routine was bad. 
+    Typically for a null pointer.
+
+-   `ICAL_NEWFAILED_ERROR`: A `new()` or `malloc()` failed.
+
+-   `ICAL_MALFORMEDDATA_ERROR`: An input string was not in the correct
+    format
+
+-   `ICAL_PARSE_ERROR`: The parser failed to parse an incoming component
+
+-   `ICAL_INTERNAL_ERROR`: Largely equivalent to an assert
+
+-   `ICAL_FILE_ERROR`: A file operation failed. Check errno for more
+    detail.
+
+-   `ICAL_ALLOCATION_ERROR`: ?
+
+-   `ICAL_USAGE_ERROR`: ?
+
+-   `ICAL_NO_ERROR`: No error
+
+-   `ICAL_MULTIPLEINCLUSION_ERROR`: ?
+
+-   `ICAL_TIMEDOUT_ERROR`: For CSTP and acquiring locks
+
+-   `ICAL_UNKNOWN_ERROR`: ?
+
+#### 5.6.3 `X-LIC-ERROR` and `X-LIC-INVALID-COMPONENT`
+
+The library handles semantic and syntactic errors in components by
+inserting errors properties into the components. If the parser cannot
+parse incoming text (a syntactic error) or if the `icalrestriction_check()`
+routine indicates that the component does not meet the requirements
+of RFC5546 (a semantic error) the library will insert properties
+of the type `X-LIC-ERROR` to describe the error. Here is an example
+of the error property:
+
+```ical
+X-LIC-ERROR;X-LIC-ERRORTYPE=INVALID_ITIP :Failed iTIP restrictions
+for property DTSTART.
+
+Expected 1 instances of the property and got 0
+```
+
+This error resulted from a call to `icalrestriction_check()`, which discovered
+that the component does not have a `DTSTART` property, as required by
+RFC5545.
+
+There are a few routines to manipulate error properties:
+
+[ The following data is supposed to be in a table. It looks OK in LyX,
+but does not format propertly in output. ]
+
++-------------------------------------+---------------------------------------------------------+
+| Routine                             | Purpose                                                 |
++-------------------------------------+---------------------------------------------------------+
+| void icalrestriction_check()        | Check a component against RFC5546 and insert            |
++-------------------------------------+---------------------------------------------------------+
+|                                     | error properties to indicate non compliance             |
++-------------------------------------+---------------------------------------------------------+
+| int icalcomponent_count_errors()    | Return the number of error properties                   |
++-------------------------------------+---------------------------------------------------------+
+|                                     | in a component                                          |
++-------------------------------------+---------------------------------------------------------+
+| void icalcomponent_strip_errors()   | Remove all error properties in as                       |
++-------------------------------------+---------------------------------------------------------+
+|                                     | component                                               |
++-------------------------------------+---------------------------------------------------------+
+| void icalcomponent_convert_errors() | Convert some error properties into                      |
++-------------------------------------+---------------------------------------------------------+
+|                                     | REQUESTS-STATUS proprties to indicate the inability to  |
++-------------------------------------+---------------------------------------------------------+
+|                                     | process the component as an iTIP request.               |
++-------------------------------------+---------------------------------------------------------+
+
+
+The types of errors are listed in icalerror.h. They are:
+
+-   `ICAL_XLICERRORTYPE_COMPONENTPARSEERROR`
+-   `ICAL_XLICERRORTYPE_PARAMETERVALUEPARSEERROR`
+-   `ICAL_XLICERRORTYPE_PARAMETERNAMEPARSEERROR`
+-   `ICAL_XLICERRORTYPE_PROPERTYPARSEERROR`
+-   `ICAL_XLICERRORTYPE_VALUEPARSEERROR`
+-   `ICAL_XLICERRORTYPE_UNKVCALPROP`
+-   `ICAL_XLICERRORTYPE_INVALIDITIP`
+
+The libical parser will generate the error that end in `PARSEERROR` when
+it encounters garbage in the input steam. `ICAL_XLICERRORTYPE_INVALIDITIP`
+is inserted by `icalrestriction_check()`, and `ICAL_XLICERRORTYPE_UNKVCALPROP`
+is generated by `icalvcal_convert()` when it encounters a vCal property
+that it cannot convert or does not know about.
+
+`icalcomponent_convert_errors()` converts some of the error properties
+in a component into `REQUEST-STATUS` properties that indicate a failure.
+As of libical version 0.18, this routine only converts `PARSEERROR` errors
+and it always generates a 3.x (failure) code. This makes it more
+of a good idea than a really useful bit of code.
+
+#### 5.6.4 `ICAL_ERRORS_ARE_FATAL` and `icalerror_errors_are_fatal`
+
+If `icalerror_get_errors_are_fatal()` returns 1, then any error
+condition will cause the program to abort. The abort occurs
+in `icalerror_set_errno()`, and is done with an assert(0) if NDEBUG
+is undefined, and with `icalerror_crash_here()` if NDEBUG is defined.
+Initially, `icalerror_get_errors_are_fatal()` is 1 when `ICAL_ERRORS_ARE_FATAL`
+is defined, and 0 otherwise. Since `ICAL_ERRORS_ARE_FATAL` is defined
+by default, `icalerror_get_errors_are_fatal()` is also set to 1 by default.
+
+You can change the compiled-in `ICAL_ERRORS_ARE_FATAL` behavior at runtime
+by calling `icalerror_set_errors_are_fatal(0)` (i.e, errors are not fatal)
+or `icalerror_set_errors_are_fatal(1)` (i.e, errors are fatal).
+
+### 5.7 Naming Standard
+
+Structures that you access with the "struct" keyword, such as `struct
+icaltimetype` are things that you are allowed to see inside and poke
+at.
+
+Structures that you access though a typedef, such as `icalcomponent`
+are things where all of the data is hidden.
+
+Component names that start with "V" are part of RFC5545 or another
+iCal standard. Component names that start with "X" are also part of
+the spec, but they are not actually components in the spec. However,
+they look and act like components, so they are components in libical.
+Names that start with `XLIC` or `X-LIC` are not part of any iCal spec.
+They are used internally by libical.
+
+Enums that identify a component, property, value or parameter end with
+`_COMPONENT`, `_PROPERTY`, `_VALUE`, or `_PARAMETER`"
+
+Enums that identify a parameter value have the name of the parameter
+as the second word. For instance: `ICAL_ROLE_REQPARTICIPANT` or 
+`ICAL_PARTSTAT_ACCEPTED`.
+
+The enums for the parts of a recurarance rule and request statuses
+are irregular.
+
+## 6 Hacks and Bugs
+
+There are a lot of hacks in the library -- bits of code that I am not
+proud of and should probably be changed. These are marked with the
+comment string "HACK."
+
+## 7 Library Reference
+
+### 7.1 Manipulating struct icaltimetype
+
+#### 7.1.1 Struct icaltimetype
+
+```c
+struct icaltimetype
+
+{
+    int year;
+    int month;
+    int day;
+    int hour;
+    int minute;
+    int second;
+    int is_utc;
+    int is_date;
+    const char* zone;
+};
+```
diff --git a/doc/UsingLibical.txt b/doc/UsingLibical.txt
index 06d3f89a..9eecded4 100644
--- a/doc/UsingLibical.txt
+++ b/doc/UsingLibical.txt
@@ -19,10 +19,11 @@ Libical implements RFC5545, RFC5546, RFC7529; the iCalendar extensions
 in RFC6638; and some of RFC6047.
 
 This documentation assumes that you are familiar with the iCalendar
-standards RFC5545 and RFC5546. these specifications are online on
-the CALSCH webpage at:
+standards RFC5545 and RFC5546. These specifications are available
+at the IETF tools website:
 
-http://www.imc.org/ietf-calendar/
+https://tools.ietf.org/html/rfc5545
+https://tools.ietf.org/html/rfc5546
 
 1.1 The libical project
 
@@ -32,10 +33,10 @@ to the project, visit http://libical.github.io/libical/
 1.2 License
 
 The code and datafiles in this distribution are licensed under the
-Mozilla Public License. See http://www.mozilla.org/NPL/MPL-1.0.html
+Mozilla Public License version 2.0. See http://www.mozilla.org/MPL
 for a copy of the license. Alternately, you may use libical under
-the terms of the GNU Library General Public License. See
-http://www.fsf.org/copyleft/lesser.html for a copy of the LGPL.
+the terms of the GNU Lesser General Public License, version 2.1.
+See http://www.gnu.org/licenses/lgpl-2.1.html for a copy of the LGPL.
 
 This dual license ensures that the library can be incorporated into
 both proprietary code and GPL'd programs, and will benefit from improvements
@@ -50,9 +51,9 @@ Also look in "src/test" for additional annotated examples.
 
 2 Building the Library
 
-Libical uses autoconf to generate makefiles. It should built with no
+Libical uses autoconf to generate makefiles. It should build with no
 adjustments on Linux, FreeBSD and Solaris under gcc. Some version
-have been successfully been build on MacOS, Solaris, UnixWare, And
+have been successfully built on MacOS, Solaris, UnixWare, and
 Tru64 UNIX without gcc, but you may run into problems with a particular
 later version.
 
@@ -147,13 +148,13 @@ Icalcomponent is a container for a set of other components and properties.
 3.1.3 Values
 
 Values are represented in a similar way to properties; a base class
-and many "derived " classes. A value is essentially a abstract handle
+and many "derived" classes. A value is essentially a abstract handle
 on a single fundamental type, a structure or a union.
 
 3.1.4 Parameters
 
 Parameters are represented in a similar way to properties, except that
-they contain only one value
+they contain only one value.
 
 3.2 Other elements of libical
 
@@ -208,7 +209,7 @@ timezone properties associated with daylight savings time starts with
 but is not defined as a component in RFC5545 (see RFC5545, section 3.6.5)
 In Libical,this grouping is represented by the XDAYLIGHT component.
 Standard iCAL components all start with the letter "V," while pseudo
-components start with"X."
+components start with "X."
 
 There are also pseudo components that are conceptually derived classes
 of VALARM. RFC5546 defines what properties may be included in each
@@ -316,7 +317,7 @@ reference, libical will either silently ignore the error or will abort
 with an error message. This behavior is controlled by a compile time
 flag (ICAL_ERRORS_ARE_FATAL), and will abort by default.
 
-5.1.2 vaargs Constructors
+5.1.2 varargs Constructors
 
 There is another way to create complex components, which is arguably
 more elegant, if you are not horrified by varargs. The varargs constructor
@@ -381,7 +382,7 @@ of code. Here is the previous examples in the vaargs style.
 
             );
 
-This form is similar to the constructor form , except that the constructors
+This form is similar to the constructor form, except that the constructors
 have "vanew" instead of "new" in the name. The arguments are similar
 too, except that the component constructor can have a list of properties,
 and the property constructor can have a list of parameters. Be sure
@@ -442,7 +443,7 @@ main() {
 
   icalparser_set_gen_data(parser,stream);
 
-  do{
+  do {
 
     line = icalparser_get_line(parser,read_stream);
 
@@ -450,17 +451,17 @@ main() {
 
     if (c != 0){
 
-     printf("%s",icalcomponent_as_ical_string(c));
+      printf("%s",icalcomponent_as_ical_string(c));
 
-     icalparser_claim(parser);
+      icalparser_claim(parser);
 
-     printf("\n---------------\n");
+      printf("\n---------------\n");
 
-     icalcomponent_free(c);
+      icalcomponent_free(c);
 
-   }
+    }
 
-  } while ( line != 0);
+  } while (line != 0);
 
 }
 
@@ -481,8 +482,7 @@ is a convenience routine;
 
 icalcomponent* icalparser_parse(icalparser *parser,
 
-               char* (*line_gen_func)(char *s, size_t size,  void*
-d))
+               char* (*line_gen_func)(char *s, size_t size,  void* d))
 
 To use this routine, you still must construct the parser object and
 pass in a reference to a line reading routine. If the parser can create
@@ -717,7 +717,7 @@ void icalproperty_remove_parameter_by_kind(
      icalparameter_kind kind);
 
 Note that since there should be only one parameter of each type in
-a property, you will rarely need to use icalparameter_get_nect_paameter.
+a property, you will rarely need to use icalparameter_get_next_parameter.
 
 5.2.6 Working with values
 
@@ -730,7 +730,7 @@ they properties that contain them. This involves fewer routine calls
 and intermediate variables than working with them independently, and
 it is type-safe.
 
-For each property, there are a _get_ and a _set_ routine that access
+For each property, there are a _get_ and a _set_ routine that accesses
 the internal value. For instanace, for the UID property, the routines
 are:
 
@@ -748,7 +748,7 @@ icalvalue* icalproperty_get_value (icalproperty* prop)
 
 void icalproperty_set_value(icalproperty* prop, icalvalue* value);
 
-Icalproperty_get_value() will return a reference that you can manipulate
+icalproperty_get_value() will return a reference that you can manipulate
 with other icalvalue routines. Most of the time, you will have to
 know what the type of the value is. For instance, if you know that
 the value is a DATETIME type, you can manipulate it with:
@@ -820,7 +820,7 @@ you want to preserve it.
 
 5.3.1 Time structure
 
-LIbical defines it's own time structure for storing all dates and times.
+Libical defines its own time structure for storing all dates and times.
 It would have been nice to re-use the C library's struct tm, but that
 structure does not differentiate between dates and times, and between
 local time and UTC. The libical structure is:
@@ -856,11 +856,11 @@ struct icaltimetype icaltime_from_timet_with_zone(time_t v,
                                                   int is_date,
                                                   icaltimezone* zone);
 
-Icaltime_from_string takes any RFC5545 compliant time string:
+icaltime_from_string takes any RFC5545 compliant time string:
 
 struct icaltimetype tt = icaltime_from_string("19970101T103000");
 
-Icaltime_from_timet_with_zone takes a timet value, representing seconds past
+icaltime_from_timet_with_zone takes a time_t value, representing seconds past
 the POSIX epoch, a flag to indicate if the time is a date, and a time zone.
 Dates have an identical structure to a time, but the time portion (hours,
 minuts and seconds) is always 00:00:00. Dates act differently in
@@ -1145,9 +1145,9 @@ and for the strings used to hold values. Some of this memory the library
 caller owns and must free, and some of the memory is managed by the
 library. Here is a summary of the memory rules.
 
-1) If the function name has "new" in it, the caller gets control
-   of the memory. ( such as icalcomponent_new(), or icalproperty_new_clone()
-   )
+1) If the function name has "new" in it (such as icalcomponent_new(),
+   or icalpropert_new_clone()), the caller gets control
+   of the memory.
 
 2) If you got the memory from a routine with new in it, you must
    call the corresponding *_free routine to free the memory. ( Use
@@ -1200,7 +1200,7 @@ to get a string that describes the error. The enumerations are:
 * ICAL_MALFORMEDDATA_ERROR -- An input string was not in the correct
   format
 
-* ICAL_PARSE_ERROR -- The parser failed to parse an incomming component
+* ICAL_PARSE_ERROR -- The parser failed to parse an incoming component
 
 * ICAL_INTERNAL_ERROR -- Largely equivalent to an assert
 
@@ -1326,7 +1326,7 @@ Names that start with "XLIC" or "X-LIC" are not part of any iCal spec.
 They are used internally by libical.
 
 Enums that identify a component, property, value or parameter end with
-"_COMPONENT," "_PROPERTY," "_VALUE," or "_PARAMETER"s
+"_COMPONENT," "_PROPERTY," "_VALUE," or "_PARAMETER"
 
 Enums that identify a parameter value have the name of the parameter
 as the second word. For instance: ICAL_ROLE_REQPARTICIPANT or ICAL_PARTSTAT_ACCEPTED.
diff --git a/doc/reference/libical-glib/CMakeLists.txt b/doc/reference/libical-glib/CMakeLists.txt
index d3fdbaaa..4013d570 100644
--- a/doc/reference/libical-glib/CMakeLists.txt
+++ b/doc/reference/libical-glib/CMakeLists.txt
@@ -1,7 +1,7 @@
-find_program(GTKDOC_SCAN gtkdoc-scan)
-find_program(GTKDOC_MKDB gtkdoc-mkdb)
-find_program(GTKDOC_MKHTML gtkdoc-mkhtml)
-find_program(GTKDOC_FIXXREF gtkdoc-fixxref)
+find_program(GTKDOC_SCAN gtkdoc-scan DOC "a tool to scan header files for public symbols")
+find_program(GTKDOC_MKDB gtkdoc-mkdb DOC "a tool to generate docbook files")
+find_program(GTKDOC_MKHTML gtkdoc-mkhtml DOC "a tool to generate documentation in html format")
+find_program(GTKDOC_FIXXREF gtkdoc-fixxref DOC "a tool to fix cross references in html files")
 
 if(NOT (GTKDOC_SCAN AND GTKDOC_MKDB AND GTKDOC_MKHTML AND GTKDOC_FIXXREF))
   message(WARNING "Cannot find all gtk-doc binaries, skipping API reference generation for libical-glib")