For Windows/x86 platforms only:
__stdcall is no longer needed for Visual Basic, so libpng-1.5.0 uses
__cdecl throughout (both API functions and callbacks) on Windows/x86
platforms.
This allows the functions
to read and write ints to be disabled independently of PNG_USE_READ_MACROS,
which allows libpng to be built with the functions even though the default
is to use the macros - this allows applications to choose at app build
time whether or not to use macros (previously impossible because the
functions weren't in the default build.)
In all prior versions of libpng most configuration options
controlled by compiler #defines had to be repeated by the
application code that used libpng. This patch changes this
so that compilation options that can only be changed at build
time are frozen in the build. Options that are compiler
dependent (and those that are system dependent) are evaluated
each time - pngconf.h holds these. Options that can be changed
per-file in the application are in png.h. Frozen options are
in the new installed header file pnglconf.h
Removed the include of sys/types.h - apparently unnecessary now on the
platforms on which it happened (all but Mac OS and RISC OS).
Moved the Mac OS test into pngpriv.h (the only place it is used.)
and callbacks.
Changed rules for generation of the various symbol files and added a new
rule for a DEF file (which is also added to the distribution).
Updated the symbol file generation to stop it adding spurious spaces
to EOL (coming from preprocessor macro expansion). Added a facility
to join tokens in the output and rewrite *.dfn to use this.
for DEF file generation.
PNG_CALLBACK added to make callback definitions uniform. PNGAPI split
into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
and appropriate changes made to all files. Cygwin builds re-hinged to
allow procedure call standard changes and to remove the need for the DEF
file (fixes build on Cygwin).
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
https://lists.sourceforge.net/lists/listinfo/png-mng-implement
to subscribe) or to glennrp at users.sourceforge.net
Glenn R-P
