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Diffstat (limited to 'projects/vstudio/readme.txt')
| -rw-r--r-- | projects/vstudio/readme.txt | 69 |
1 files changed, 20 insertions, 49 deletions
diff --git a/projects/vstudio/readme.txt b/projects/vstudio/readme.txt index 66c4e6789..1d8b99e0e 100644 --- a/projects/vstudio/readme.txt +++ b/projects/vstudio/readme.txt @@ -1,7 +1,7 @@ VisualStudio instructions -libpng version 1.4.9beta01 - July 8, 2011 +libpng version 1.5.10beta01 - February 19, 2012 Copyright (c) 1998-2010 Glenn Randers-Pehrson @@ -13,29 +13,13 @@ This directory contains support for building libpng under MicroSoft VisualStudio 2010. It may also work under later versions of VisualStudio. You should be familiar with VisualStudio before using this directory. -This is a slightly modified copy of the 'vstudio' solution from libpng -1.5; it is intended to provide compatibility for libpng 1.4 with later -releases of zlib (from 1.2.4) and to provide a migration aid for 1.5. - -A 'VB' DLL is no longer produced - use the standard 'Release' DLL. - Initial preparations ==================== -You should install the 'official' build of zlib on your system - follow the -instructions provided on http://www.zlib.net. When a new release is being -made of zlib the instructions disappear for a while until the new official -build is available. You will have to wait. - You must enter some information in zlib.props before attempting to build with this 'solution'. Please read and edit zlib.props first. You will probably not be familiar with the contents of zlib.props - do not worry, it is mostly harmless. -Make sure that your official build layout matches the requirements listed -in zlib.props. Prior to zlib-1.2.4 the official build (1.2.3) placed -include and library files in different directories - if you find this -has happened just put them all in the same directory. - This is all you need to do to build the 'release' and 'release library' configurations. @@ -46,6 +30,25 @@ information is produced (in the .pdb), but if you encounter a problem the optimization may make it difficult to debug. Simply rebuild with a lower optimization level (e.g. /Od.) +Linking your application +======================== +Normally you should link against the 'release' configuration. This builds a +DLL for libpng 1.5 with the default runtime options used by Visual Studio +2010. In particular the runtime library is the "MultiThreaded DLL" version. +If you use Visual Studio defaults to build your application you will have no +problems. + +If you don't use the Visual Studio defaults your application must still be built +with the default runtime option (/MD). If, for some reason, it is not then your +application will crash inside libpng15.dll as soon as libpng tries to read +from a file handle you pass in. + +If you do not want to use the DLL, for example for a very small application, +the 'release library' configuration may be more appropriate. This is built +with a non-standard runtime library - the "MultiThreaded" version. When you +build your application it must be compiled with this option (/MT), otherwise +it will not build (if you are lucky) or crash (if you are not.) + Stop reading here ================= You have enough information to build a working application. @@ -57,37 +60,5 @@ do not need these unless your own solution itself uses debug builds (it is far more effective to debug on the release builds, there is no point building a special debug build.) -If, despite the previous paragraph, you still feel you need a debug build you -will have to download the zlib source as well (http://www.zlib.net) and include -the directory where you unpack it in zlib.props. This solution will then be -able to build a minimal zlib sufficient for libpng. This build is only -suitable for making a debug libpng. - The debug build of libpng is minimally supported. Support for debug builds of zlib is also minimal. You really don't want to do this. - -This solution only supports the Multi-Threaded DLL C Runtime -============================================================ -If you examine the solution you will find that it very deliberately lists -exactly which MicroSoft DLLs it is linking against. It explicitly links -against msvcrt.lib. The debug version links against msvcrtd.lib (this is -why it is a debug version - it's nothing to do with having any special -debug support, it doesn't). - -These versions of the MicroSoft C runtime correspond to the compiler flags -/MD (release) and /MDd (debug) - the "Multi-Threaded DLL" implementation of the -C runtime library. - -If you need to change this then you will have to make sure that both the -compiler flags and the ".lib" in the linker dependences match up. Fortunately -neither zlib nor libpng require libraries other than a C runtime and -kernel32. - -You cannot pass (FILE*) objects from a different runtime (including msvcrtd -to msvcrt) to libpng. If you do then your program will crash within libpng -when it first makes a file read or write call. - -It is likely if you have read this far that you have found you can't avoid -having multiple C runtimes in your program. This is OK, it does work, but -you will have to implement the libpng file read/write callbacks rather than -using the internal libpng default. This is easy. |