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Diffstat (limited to 'doc/gawk.texi')
| -rw-r--r-- | doc/gawk.texi | 105 |
1 files changed, 65 insertions, 40 deletions
diff --git a/doc/gawk.texi b/doc/gawk.texi index 713f5a46..f0c7d6e6 100644 --- a/doc/gawk.texi +++ b/doc/gawk.texi @@ -742,6 +742,7 @@ particular records in a file and perform operations upon them. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -29575,6 +29576,7 @@ This (rather large) @value{SECTION} describes the API in detail. * Extension API Functions Introduction:: Introduction to the API functions. * General Data Types:: The data types. * Requesting Values:: How to get a value. +* Memory Allocation Functions:: Functions for allocating memory. * Constructor Functions:: Functions for creating values. * Registration Functions:: Functions to register things with @command{gawk}. @@ -29668,10 +29670,8 @@ corresponding standard header file @emph{before} including @file{gawkapi.h}: @item @code{EOF} @tab @code{<stdio.h>} @item @code{FILE} @tab @code{<stdio.h>} @item @code{NULL} @tab @code{<stddef.h>} -@item @code{malloc()} @tab @code{<stdlib.h>} @item @code{memcpy()} @tab @code{<string.h>} @item @code{memset()} @tab @code{<string.h>} -@item @code{realloc()} @tab @code{<stdlib.h>} @item @code{size_t} @tab @code{<sys/types.h>} @item @code{struct stat} @tab @code{<sys/stat.h>} @end multitable @@ -29701,7 +29701,7 @@ does not support this keyword, you should either place All pointers filled in by @command{gawk} are to memory managed by @command{gawk} and should be treated by the extension as read-only. Memory for @emph{all} strings passed into @command{gawk} -from the extension @emph{must} come from @code{malloc()} and is managed +from the extension @emph{must} come from calling the api-provided function pointers @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()} and is managed by @command{gawk} from then on. @item @@ -29784,7 +29784,7 @@ A simple boolean type. This represents a mutable string. @command{gawk} owns the memory pointed to if it supplied the value. Otherwise, it takes ownership of the memory pointed to. -@strong{Such memory must come from @code{malloc()}!} +@strong{Such memory must come from calling the api-provided function pointers @code{api_malloc()}, @code{api_calloc()}, or @code{api_realloc()}!} As mentioned earlier, strings are maintained using the current multibyte encoding. @@ -29946,44 +29946,33 @@ value type, as appropriate. This behavior is summarized in @end float @end ifplaintext -@node Constructor Functions -@subsection Constructor Functions and Convenience Macros +@node Memory Allocation Functions +@subsection Memory Allocation Functions and Convenience Macros -The API provides a number of @dfn{constructor} functions for creating -string and numeric values, as well as a number of convenience macros. -This @value{SUBSECTION} presents them all as function prototypes, in -the way that extension code would use them. +The API provides a number of @dfn{memory allocation} functions for +allocating memory that can be passed to gawk, as well as a number of convenience macros. @table @code -@item static inline awk_value_t * -@itemx make_const_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a C string constant -(or other string data), and automatically creates a @emph{copy} of the data -for storage in @code{result}. It returns @code{result}. +@item void *gawk_malloc(size_t size); +Call @command{gawk}-provided @code{api_malloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) -This function creates a string value in the @code{awk_value_t} variable -pointed to by @code{result}. It expects @code{string} to be a @samp{char *} -value pointing to data previously obtained from @code{malloc()}. The idea here -is that the data is passed directly to @command{gawk}, which assumes -responsibility for it. It returns @code{result}. +@item void *gawk_calloc(size_t nmemb, size_t size); +Call @command{gawk}-provided @code{api_calloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_null_string(awk_value_t *result) -This specialized function creates a null string (the ``undefined'' value) -in the @code{awk_value_t} variable pointed to by @code{result}. -It returns @code{result}. +@item void *gawk_realloc(void *ptr, size_t size); +Call @command{gawk}-provided @code{api_realloc()} to allocate storage that may +be passed to @command{gawk}. -@item static inline awk_value_t * -@itemx make_number(double num, awk_value_t *result) -This function simply creates a numeric value in the @code{awk_value_t} variable -pointed to by @code{result}. +@item void gawk_free(void *ptr); +Call @command{gawk}-provided @code{api_free()} to release storage that was +allocated with @code{gawk_malloc()}, @code{gawk_calloc()} or @code{gawk_realloc()}. @end table -Two convenience macros may be used for allocating storage from @code{malloc()} -and @code{realloc()}. If the allocation fails, they cause @command{gawk} to + +Two convenience macros may be used for allocating storage from the api-provided function pointers @code{api_malloc()} +and @code{api_realloc()}. If the allocation fails, they cause @command{gawk} to exit with a fatal error message. They should be used as if they were procedure calls that do not return a value. @@ -29996,7 +29985,7 @@ The arguments to this macro are as follows: The pointer variable to point at the allocated storage. @item type -The type of the pointer variable, used to create a cast for the call to @code{malloc()}. +The type of the pointer variable, used to create a cast for the call to @code{api_malloc()}. @item size The total number of bytes to be allocated. @@ -30020,11 +30009,47 @@ make_malloced_string(message, strlen(message), & result); @end example @item #define erealloc(pointer, type, size, message) @dots{} -This is like @code{emalloc()}, but it calls @code{realloc()}, -instead of @code{malloc()}. +This is like @code{emalloc()}, but it calls @code{api_realloc()}, +instead of @code{api_malloc()}. The arguments are the same as for the @code{emalloc()} macro. @end table +@node Constructor Functions +@subsection Constructor Functions + +The API provides a number of @dfn{constructor} functions for creating +string and numeric values, as well as a number of convenience macros. +This @value{SUBSECTION} presents them all as function prototypes, in +the way that extension code would use them. + +@table @code +@item static inline awk_value_t * +@itemx make_const_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a C string constant +(or other string data), and automatically creates a @emph{copy} of the data +for storage in @code{result}. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_malloced_string(const char *string, size_t length, awk_value_t *result) +This function creates a string value in the @code{awk_value_t} variable +pointed to by @code{result}. It expects @code{string} to be a @samp{char *} +value pointing to data previously obtained from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The idea here +is that the data is passed directly to @command{gawk}, which assumes +responsibility for it. It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_null_string(awk_value_t *result) +This specialized function creates a null string (the ``undefined'' value) +in the @code{awk_value_t} variable pointed to by @code{result}. +It returns @code{result}. + +@item static inline awk_value_t * +@itemx make_number(double num, awk_value_t *result) +This function simply creates a numeric value in the @code{awk_value_t} variable +pointed to by @code{result}. +@end table + @node Registration Functions @subsection Registration Functions @@ -30072,7 +30097,7 @@ This is a pointer to the C function that provides the desired functionality. The function must fill in the result with either a number or a string. @command{gawk} takes ownership of any string memory. -As mentioned earlier, string memory @strong{must} come from @code{malloc()}. +As mentioned earlier, string memory @strong{must} come from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. The @code{num_actual_args} argument tells the C function how many actual parameters were passed from the calling @command{awk} code. @@ -30810,7 +30835,7 @@ assign those values to variables using @code{sym_update()} or @code{sym_update_scalar()}, as you like. However, you can understand the point of cached values if you remember that -@emph{every} string value's storage @emph{must} come from @code{malloc()}. +@emph{every} string value's storage @emph{must} come from @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()}. If you have 20 variables, all of which have the same string value, you must create 20 identical copies of the string.@footnote{Numeric values are clearly less problematic, requiring only a C @code{double} to store.} @@ -31007,7 +31032,7 @@ requires that you understand how such values are converted to strings (@pxref{Conversion}); thus using integral values is safest. As with @emph{all} strings passed into @code{gawk} from an extension, -the string value of @code{index} must come from @code{malloc()}, and +the string value of @code{index} must come from the api-provided functions @code{api_malloc()}, @code{api_calloc()} or @code{api_realloc()} and @command{gawk} releases the storage. @item awk_bool_t set_array_element(awk_array_t a_cookie, |