Fix G_STMT_START / G_STMT_END on Solaris. (#321972, Andrew Paprocki)

2005-11-28  Matthias Clasen  <mclasen@redhat.com>

        Fix G_STMT_START / G_STMT_END on Solaris.  (#321972,
        Andrew Paprocki)

        * configure.in: Check whether do { } while (0) works.

        * glib/gmacros.h: Use do { } while (0) for G_STMT_START /
        G_STMT_END if it works.

ChangeLog

@@ -1,3 +1,13 @@
+2005-11-28  Matthias Clasen  <mclasen@redhat.com>
+
+	Fix G_STMT_START / G_STMT_END on Solaris.  (#321972,
+	Andrew Paprocki)
+	
+	* configure.in: Check whether do { } while (0) works.
+
+	* glib/gmacros.h: Use do { } while (0) for G_STMT_START / 
+	G_STMT_END if it works.
+	
 2005-11-28  Matthias Clasen  <mclasen@redhat.com>
 
 	* glib/gthread.c (g_static_rw_lock_wait, g_static_rw_lock_signal): 

ChangeLog.pre-2-10

@@ -1,3 +1,13 @@
+2005-11-28  Matthias Clasen  <mclasen@redhat.com>
+
+	Fix G_STMT_START / G_STMT_END on Solaris.  (#321972,
+	Andrew Paprocki)
+	
+	* configure.in: Check whether do { } while (0) works.
+
+	* glib/gmacros.h: Use do { } while (0) for G_STMT_START / 
+	G_STMT_END if it works.
+	
 2005-11-28  Matthias Clasen  <mclasen@redhat.com>
 
 	* glib/gthread.c (g_static_rw_lock_wait, g_static_rw_lock_signal): 

ChangeLog.pre-2-12

@@ -1,3 +1,13 @@
+2005-11-28  Matthias Clasen  <mclasen@redhat.com>
+
+	Fix G_STMT_START / G_STMT_END on Solaris.  (#321972,
+	Andrew Paprocki)
+	
+	* configure.in: Check whether do { } while (0) works.
+
+	* glib/gmacros.h: Use do { } while (0) for G_STMT_START / 
+	G_STMT_END if it works.
+	
 2005-11-28  Matthias Clasen  <mclasen@redhat.com>
 
 	* glib/gthread.c (g_static_rw_lock_wait, g_static_rw_lock_signal): 

configure.in

@@ -700,6 +700,21 @@ main (void) {
 }],[g_can_inline=yes],[g_can_inline=no])
 AC_MSG_RESULT($g_can_inline)
 
+dnl *** check for working do while(0) macros ***
+AC_CACHE_CHECK([for working do while(0) macros], g_support_dowhile_macros, [
+	AC_TRY_COMPILE([],[
+	#define STMT_START do
+	#define STMT_END while(0)
+	#define STMT_TEST STMT_START { i = 0; } STMT_END
+	int main(void) { int i = 1; STMT_TEST; return i; }],
+	[g_support_dowhile_macros=yes],
+	[g_support_dowhile_macros=no],
+	[g_support_dowhile_macros=yes])
+])
+if test x$g_support_dowhile_macros = xyes; then
+  AC_DEFINE(HAVE_DOWHILE_MACROS, 1, [define for working do while(0) macros])
+fi
+
 # check for flavours of varargs macros
 AC_MSG_CHECKING(for ISO C99 varargs macros in C)
 AC_TRY_COMPILE([],[

glib/gmacros.h

@@ -194,23 +194,26 @@
  *  can be used as a single statement, as in
  *  if (x) G_STMT_START { ... } G_STMT_END; else ...
  *
- *  For gcc we will wrap the statements within `({' and `})' braces.
+ *  When GCC is compiling C code in non-ANSI mode, it will use the
- *  For SunOS they will be wrapped within `if (1)' and `else (void) 0',
+ *  compiler __extension__ to wrap the statements wihin `({' and '})' braces.
- *  and otherwise within `do' and `while (0)'.
+ *  When compiling on platforms where configure has defined
+ *  HAVE_DOWHILE_MACROS, statements will be wrapped with `do' and `while (0)'.
+ *  For any other platforms (SunOS4 is known to have this issue), wrap the
+ *  statements with `if (1)' and `else (void) 0'.
  */
 #if !(defined (G_STMT_START) && defined (G_STMT_END))
-#  if defined (__GNUC__) && !defined (__STRICT_ANSI__) && !defined (__cplusplus)
+# if defined (__GNUC__) && !defined (__STRICT_ANSI__) && !defined (__cplusplus)
-#    define G_STMT_START	(void) __extension__ (
+#  define G_STMT_START (void) __extension__ (
-#    define G_STMT_END		)
+#  define G_STMT_END )
-#  else
+# else /* !(__GNUC__ && !__STRICT_ANSI__ && !__cplusplus) */
-#    if (defined (sun) || defined (__sun__))
+#  if defined (HAVE_DOWHILE_MACROS)
-#      define G_STMT_START	if (1)
+#   define G_STMT_START do
-#      define G_STMT_END	else (void)0
+#   define G_STMT_END while (0)
-#    else
+#  else /* !HAVE_DOWHILE_MACROS */
-#      define G_STMT_START	do
+#   define G_STMT_START if (1)
-#      define G_STMT_END	while (0)
+#   define G_STMT_END else (void) 0
-#    endif
+#  endif /* !HAVE_DOWHILE_MACROS */
-#  endif
+# endif /* !(__GNUC__ && !__STRICT_ANSI__ && !__cplusplus) */
 #endif
 
 /* Allow the app programmer to select whether or not return values