[devel] Added appropriate feature test macros (_POSIX_SOURCE, _ISOC99_SOURCE)

to ensure libpng sees the correct API.

ANNOUNCE

 
-Libpng 1.5.3beta05 - April 29, 2011
+Libpng 1.5.3beta05 - May 4, 2011
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -76,7 +76,12 @@ Version 1.5.3beta04 [April 27, 2011]
   Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
     avoid a clash with the png_jmpbuf macro on some platforms.
 
-Version 1.5.3beta05 [April 29, 2011]
+Version 1.5.3beta05 [May 4, 2011]
+  Added appropriate feature test macros to ensure libpng sees the correct API
+   _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and pngvalid.c to ensure
+    that POSIX conformant systems disable non-POSIX APIs.  _ISOC99_SOURCE is
+    defined in pngpriv.h to obtain the ISO C99 snprintf definition, when
+    available.
 
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CHANGES

@@ -3337,7 +3337,12 @@ Version 1.5.3beta04 [April 27, 2011]
   Changed png_struct jmp_buf member name from png_jmpbuf to tmp_jmpbuf to
     avoid a possible clash with the png_jmpbuf macro on some platforms.
 
-Version 1.5.3beta05 [April 29, 2011]
+Version 1.5.3beta05 [May 4, 2011]
+  Added appropriate feature test macros to ensure libpng sees the correct API
+   _POSIX_SOURCE is defined in pngpriv.h, pngtest.c and pngvalid.c to ensure
+    that POSIX conformant systems disable non-POSIX APIs.  _ISOC99_SOURCE is
+    defined in pngpriv.h to obtain the ISO C99 snprintf definition, when
+    available.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

pngpriv.h

@@ -25,6 +25,21 @@
 #ifndef PNGPRIV_H
 #define PNGPRIV_H
 
+/* Feature Test Macros.  The following are defined here to ensure that correctly
+ * implemented libraries reveal the APIs libpng needs to build and hide those
+ * that are not needed and potentially damaging to the compilation.
+ *
+ * Feature Test Macros must be defined before any system header is included (see
+ * POSIX 1003.1 2.8.2 "POSIX Symbols."
+ *
+ * These macros only have an effect if the operating system supports either
+ * POSIX 1003.1 or C99, or both.  On other operating systems (particularly
+ * Windows/Visual Studio) there is no effect; the OS specific tests below are
+ * still required (as of 2011-05-02.)
+ */
+#define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+#define _ISOC99_SOURCE 1 /* for snprintf */
+
 /* This is required for the definition of abort(), used as a last ditch
  * error handler when all else fails.
  */

pngtest.c

@@ -31,6 +31,8 @@
  * of files at once by typing "pngtest -m file1.png file2.png ..."
  */
 
+#define _POSIX_SOURCE 1
+
 #include "zlib.h"
 #include "png.h"
 /* Copied from pngpriv.h but only used in error messages below. */

pngvalid.c

@@ -19,6 +19,8 @@
  *   transformations performed by libpng.
  */
 
+#define _POSIX_SOURCE 1
+
 #include "png.h"
 #if PNG_LIBPNG_VER < 10500
 /* This delibarately lacks the PNG_CONST. */