Use <stdbool.h> instead of locally defined bool

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1949 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 38 insertions, 24 deletions

diff --git a/lib/util/pm_c_util.h b/lib/util/pm_c_util.h
index f17d1e03..79897cf0 100644
--- a/lib/util/pm_c_util.h
+++ b/lib/util/pm_c_util.h
@@ -41,35 +41,49 @@
    use "int".
 */
 
-/* We used to assume that if TRUE was defined, then bool was too.
-   However, we had a report on 2001.09.21 of a Tru64 system that had
-   TRUE but not bool and on 2002.03.21 of an AIX 4.3 system that was
-   likewise.  So now we define bool all the time, unless the macro
-   HAVE_BOOL is defined.  If someone is using the Netpbm libraries and
-   also another library that defines bool, he can either make the
-   other library define/respect HAVE_BOOL or just define HAVE_BOOL in
-   the file that includes pm_config.h or with a compiler option.  Note
-   that C++ always has bool.  
+/* We will probably never again see a system that does not have
+   <stdbool.h>, but just in case, we have our own alternative here.
 
-   A preferred way of getting booleans is <stdbool.h>.  But it's not
-   available on all platforms, and it's easy to reproduce what it does
-   here.
+   Evidence shows that the compiler actually produces better code with
+   <stdbool.h> than with bool simply typedefed to int.
 */
+
+#ifdef __cplusplus
+  /* C++ has a bool type and false and true constants built in. */
+#else
+  /* The test for __STDC__ is paranoid.  It is there just in case some
+     nonstandard compiler defines __STDC_VERSION__ in an arbitrary manner.
+  */
+  #if ( defined(__GNUC__) && (__GNUC__ >= 3) ) || \
+      ( defined(__STDC__) && (__STDC__ ==1) && \
+        defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) ) 
+    #include <stdbool.h>
+  #else
+    /* We used to assume that if TRUE was defined, then bool was too.
+       However, we had a report on 2001.09.21 of a Tru64 system that had
+       TRUE but not bool and on 2002.03.21 of an AIX 4.3 system that was
+       likewise.  So now we define bool all the time, unless the macro
+       HAVE_BOOL is defined.  If someone is using the Netpbm libraries and
+       also another library that defines bool, he can either make the
+       other library define/respect HAVE_BOOL or just define HAVE_BOOL in
+       the file that includes pm_config.h or with a compiler option.  Note
+       that C++ always has bool.  
+    */
+    #ifndef HAVE_BOOL
+      #define HAVE_BOOL 1
+      typedef int bool;
+    #endif
+    #ifndef true
+      enum boolvalue {false=0, true=1};
+    #endif
+  #endif
+#endif
+
 #ifndef TRUE
-  #define TRUE 1
+  #define TRUE true
   #endif
 #ifndef FALSE
-  #define FALSE 0
-  #endif
-/* C++ has a bool type and false and true constants built in. */
-#ifndef __cplusplus
-  #ifndef HAVE_BOOL
-    #define HAVE_BOOL 1
-    typedef int bool;
-    #endif
-  #ifndef true
-    enum boolvalue {false=0, true=1};
-    #endif
+#define FALSE false
   #endif
 
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))