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	In <https://sourceware.org/ml/libc-alpha/2014-11/msg00326.html>, Roland requested internal macros for use of "#pragma GCC diagnostic". This patch adds such macros and uses them to disable -Wformat warnings for some code testing GNU scanf %as where GCC expects C99 scanf %a (several other stdio tests currently use -Wno-format to disable warnings). Limitations in GCC's diagnostic pragmas require separate macros before and after the code generating the warnings, rather than a single macro taking that code as an argument. The macros are named DIAG_*_NEEDS_COMMENT to emphasise to reviewers the need for a comment accompanying any use of them (such comments may however just appear once for several uses of the macros for the same issue in the same file). I put a GCC version in the arguments to DIAG_IGNORE_NEEDS_COMMENT, as that seems something useful to grep for when obsoleting support for an old GCC version and needing to decide if warning-disabling code is still relevant. These macros should be usable for replacing existing -Wno-* use in makefiles (as also suggested by Roland), though I have no plans to work on that (only on use of the macros in cases where warnings are currently present that need disabling to use -Werror). Tested for x86_64. * include/libc-internal.h (DIAG_PUSH_NEEDS_COMMENT): New macro. (DIAG_POP_NEEDS_COMMENT): Likewise. (_DIAG_STR1): Likewise. (_DIAG_STR): Likewise. (DIAG_IGNORE_NEEDS_COMMENT): Likewise. * stdio-common/bug21.c: Include <libc-internal.h>. (do_test): Disable -Wformat around call to sscanf. * stdio-common/scanf14.c: Include <libc-internal.h>. (main): Disable -Wformat around some calls to scanf functions.
		
			
				
	
	
		
			138 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			138 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| #include <stdio.h>
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| #include <stdlib.h>
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| #include <string.h>
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| #include <wchar.h>
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| #include <libc-internal.h>
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| 
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| #define FAIL() \
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|   do {							\
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|     result = 1;						\
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|     printf ("test at line %d failed\n", __LINE__);	\
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|   } while (0)
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| 
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| int
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| main (void)
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| {
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|   wchar_t *lsp;
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|   char *sp;
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|   float f;
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|   double d;
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|   char c[8];
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|   int result = 0;
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| 
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|   if (sscanf (" 0.25s x", "%e%3c", &f, c) != 2)
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|     FAIL ();
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|   else if (f != 0.25 || memcmp (c, "s x", 3) != 0)
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|     FAIL ();
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|   /* GCC in C99 mode treats %a as the C99 format expecting float *,
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|      but glibc with _GNU_SOURCE treats %as as the GNU allocation
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|      extension, so resulting in "warning: format '%a' expects argument
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|      of type 'float *', but argument 3 has type 'char **'".  This
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|      applies to the other %as, %aS and %a[] formats below as well.  */
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|   DIAG_PUSH_NEEDS_COMMENT;
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|   DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
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|   if (sscanf (" 1.25s x", "%as%2c", &sp, c) != 2)
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|     FAIL ();
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|   else
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|     {
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|       if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
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| 	FAIL ();
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|       memset (sp, 'x', sizeof "1.25s");
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|       free (sp);
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|     }
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|   DIAG_POP_NEEDS_COMMENT;
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|   if (sscanf (" 2.25s x", "%las%2c", &d, c) != 2)
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|     FAIL ();
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|   else if (d != 2.25 || memcmp (c, " x", 2) != 0)
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|     FAIL ();
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|   /* See explanation above.  */
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|   DIAG_PUSH_NEEDS_COMMENT;
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|   DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
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|   if (sscanf (" 3.25S x", "%4aS%3c", &lsp, c) != 2)
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|     FAIL ();
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|   else
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|     {
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|       if (wcscmp (lsp, L"3.25") != 0 || memcmp (c, "S x", 3) != 0)
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| 	FAIL ();
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|       memset (lsp, 'x', sizeof L"3.25");
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|       free (lsp);
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|     }
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|   if (sscanf ("4.25[0-9.] x", "%a[0-9.]%8c", &sp, c) != 2)
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|     FAIL ();
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|   else
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|     {
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|       if (strcmp (sp, "4.25") != 0 || memcmp (c, "[0-9.] x", 8) != 0)
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| 	FAIL ();
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|       memset (sp, 'x', sizeof "4.25");
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|       free (sp);
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|     }
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|   DIAG_POP_NEEDS_COMMENT;
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|   if (sscanf ("5.25[0-9.] x", "%la[0-9.]%2c", &d, c) != 2)
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|     FAIL ();
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|   else if (d != 5.25 || memcmp (c, " x", 2) != 0)
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|     FAIL ();
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| 
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|   const char *tmpdir = getenv ("TMPDIR");
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|   if (tmpdir == NULL || tmpdir[0] == '\0')
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|     tmpdir = "/tmp";
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| 
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|   char fname[strlen (tmpdir) + sizeof "/tst-scanf14.XXXXXX"];
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|   sprintf (fname, "%s/tst-scanf14.XXXXXX", tmpdir);
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|   if (fname == NULL)
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|     FAIL ();
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| 
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|   /* Create a temporary file.   */
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|   int fd = mkstemp (fname);
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|   if (fd == -1)
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|     FAIL ();
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| 
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|   FILE *fp = fdopen (fd, "w+");
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|   if (fp == NULL)
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|     FAIL ();
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|   else
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|     {
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|       if (fputs (" 1.25s x", fp) == EOF)
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| 	FAIL ();
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|       if (fseek (fp, 0, SEEK_SET) != 0)
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| 	FAIL ();
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|       /* See explanation above.  */
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|       DIAG_PUSH_NEEDS_COMMENT;
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|       DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
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|       if (fscanf (fp, "%as%2c", &sp, c) != 2)
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| 	FAIL ();
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|       else
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| 	{
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| 	  if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
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| 	    FAIL ();
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| 	  memset (sp, 'x', sizeof "1.25s");
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| 	  free (sp);
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| 	}
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|       DIAG_POP_NEEDS_COMMENT;
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| 
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|       if (freopen (fname, "r", stdin) == NULL)
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| 	FAIL ();
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|       else
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| 	{
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| 	  /* See explanation above.  */
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| 	  DIAG_PUSH_NEEDS_COMMENT;
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| 	  DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
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| 	  if (scanf ("%as%2c", &sp, c) != 2)
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| 	    FAIL ();
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| 	  else
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| 	    {
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| 	      if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
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| 		FAIL ();
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| 	      memset (sp, 'x', sizeof "1.25s");
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| 	      free (sp);
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| 	    }
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| 	  DIAG_POP_NEEDS_COMMENT;
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| 	}
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| 
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|       fclose (fp);
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|     }
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| 
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|   remove (fname);
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| 
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|   return result;
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| }
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