Re: C99 assert

[Eric Blake <ebb9 at byu dot net>]

Jeff Johnston <jjohnstn <at> redhat.com> writes:

> 
> Hi Eric,
> 
>    I'd like to see backward-compatiblity to be the old-style message 
> format.  I don't see the point of saying: function <blank>.  So, old 
> compiled calls to __assert would behave as they always have.  Similarly, 
> for systems without function capability, I would like to use the old 
> message format.  My take would be to have both __assert and 
> __assert_func and have assert map to the appropriate call.  I also think 
> that the function should be quoted or you should use a colon (e.g. 
> function: getparms) for clarification.
> 

How about the following, then?

2007-06-26  Eric Blake  <ebb9@byu.net>

	Support __func__ in assert, as required by C99.
	* libc/stdlib/assert.c (__assert_func): New function.
	(__assert): Use __assert_func.
	* libc/include/assert.h (assert) [!NDEBUG]: Use __assert_func when
	possible.

Index: libc/include/assert.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/assert.h,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 assert.h
--- libc/include/assert.h	17 Feb 2000 19:39:46 -0000	1.1.1.1
+++ libc/include/assert.h	26 Jun 2007 20:01:28 -0000
@@ -11,18 +11,26 @@ extern "C" {
 #undef assert
 
 #ifdef NDEBUG           /* required by ANSI standard */
-#define assert(p)  	((void)0)
+# define assert(p)	((void)0)
 #else
+# define assert(e) ((e) ? (void)0 : __assert_func (__FILE__, __LINE__, \
+                                                   __ASSERT_FUNC, #e))
+#endif /* NDEBUG */
 
-#ifdef __STDC__
-#define assert(e)       ((e) ? (void)0 : __assert(__FILE__, __LINE__, #e))
-#else   /* PCC */
-#define assert(e)       ((e) ? (void)0 : __assert(__FILE__, __LINE__, "e"))
+#ifdef __cplusplus && defined __GNUC__
+  /* Use g++'s demangled names.  */
+# define __ASSERT_FUNC __PRETTY_FUNCTION__
+#elif __cplusplus || __STDC_VERSION__ < 199901L
+  /* C++03 and C89 do not have __func__.  */
+# define __ASSERT_FUNC ((char*) 0)
+#else /* C99 compatible */
+# define __ASSERT_FUNC __func__
 #endif
 
-#endif /* NDEBUG */
-
-void _EXFUN(__assert,(const char *, int, const char *));
+void _EXFUN(__assert,(const char *, int, const char *)
+            _ATTRIBUTE ((__noreturn__)));
+void _EXFUN(__assert_func,(const char *, int, const char *, const char *)
+            _ATTRIBUTE ((__noreturn__)));
 
 #ifdef __cplusplus
 }
Index: libc/stdlib/assert.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/stdlib/assert.c,v
retrieving revision 1.2
diff -u -p -r1.2 assert.c
--- libc/stdlib/assert.c	28 Oct 2005 21:21:07 -0000	1.2
+++ libc/stdlib/assert.c	26 Jun 2007 20:01:28 -0000
@@ -9,11 +9,6 @@ ANSI_SYNOPSIS
 	#include <assert.h>
 	void assert(int <[expression]>);
 
-TRAD_SYNOPSIS
-	#include <assert.h>
-	assert(<[expression]>)
-	int <[expression]>;
-
 DESCRIPTION
 	Use this macro to embed debuggging diagnostic statements in
 	your programs.  The argument <[expression]> should be an
@@ -24,7 +19,11 @@ DESCRIPTION
 	calls <<abort>>, after first printing a message showing what
 	failed and where:
 
-. Assertion failed: <[expression]>, file <[filename]>, line <[lineno]>
+. Assertion failed: <[expression]>, file <[filename]>, line <[lineno]>, 
function: <[func]>
+
+	If the name of the current function is not known (for example,
+	when using a C89 compiler that does not understand __func__),
+	the function is omitted.
 
 	The macro is defined to permit you to turn off all uses of
 	<<assert>> at compile time by defining <<NDEBUG>> as a
@@ -48,15 +47,28 @@ Supporting OS subroutines required (only
 #include <stdlib.h>
 #include <stdio.h>
 
+/* func can be NULL, in which case no function information is given.  */
 void
-_DEFUN (__assert, (file, line, failedexpr),
+_DEFUN (__assert_func, (file, line, func, failedexpr),
 	const char *file _AND
 	int line _AND
+	const char *func _AND
 	const char *failedexpr)
 {
-  (void)fiprintf(stderr,
-	"assertion \"%s\" failed: file \"%s\", line %d\n",
-	failedexpr, file, line);
+  fiprintf(stderr,
+	   "assertion \"%s\" failed: file \"%s\", line %d%s%s\n",
+	   failedexpr, file, line,
+           func ? ", function: " : "", func ? func : "");
   abort();
   /* NOTREACHED */
 }
+
+void
+_DEFUN (__assert, (file, line, failedexpr),
+	const char *file _AND
+	int line _AND
+	const char *failedexpr)
+{
+   __assert_func (file, line, NULL, failedexpr);
+  /* NOTREACHED */
+}