glibc/stdio-common/scanf14.c
Joseph Myers 2084e7ca4d Add macros for diagnostic control, use for scanf %a tests.
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.
2014-12-10 00:41:19 +00:00

138 lines
3.2 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <libc-internal.h>
#define FAIL() \
do { \
result = 1; \
printf ("test at line %d failed\n", __LINE__); \
} while (0)
int
main (void)
{
wchar_t *lsp;
char *sp;
float f;
double d;
char c[8];
int result = 0;
if (sscanf (" 0.25s x", "%e%3c", &f, c) != 2)
FAIL ();
else if (f != 0.25 || memcmp (c, "s x", 3) != 0)
FAIL ();
/* GCC in C99 mode treats %a as the C99 format expecting float *,
but glibc with _GNU_SOURCE treats %as as the GNU allocation
extension, so resulting in "warning: format '%a' expects argument
of type 'float *', but argument 3 has type 'char **'". This
applies to the other %as, %aS and %a[] formats below as well. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
if (sscanf (" 1.25s x", "%as%2c", &sp, c) != 2)
FAIL ();
else
{
if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
FAIL ();
memset (sp, 'x', sizeof "1.25s");
free (sp);
}
DIAG_POP_NEEDS_COMMENT;
if (sscanf (" 2.25s x", "%las%2c", &d, c) != 2)
FAIL ();
else if (d != 2.25 || memcmp (c, " x", 2) != 0)
FAIL ();
/* See explanation above. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
if (sscanf (" 3.25S x", "%4aS%3c", &lsp, c) != 2)
FAIL ();
else
{
if (wcscmp (lsp, L"3.25") != 0 || memcmp (c, "S x", 3) != 0)
FAIL ();
memset (lsp, 'x', sizeof L"3.25");
free (lsp);
}
if (sscanf ("4.25[0-9.] x", "%a[0-9.]%8c", &sp, c) != 2)
FAIL ();
else
{
if (strcmp (sp, "4.25") != 0 || memcmp (c, "[0-9.] x", 8) != 0)
FAIL ();
memset (sp, 'x', sizeof "4.25");
free (sp);
}
DIAG_POP_NEEDS_COMMENT;
if (sscanf ("5.25[0-9.] x", "%la[0-9.]%2c", &d, c) != 2)
FAIL ();
else if (d != 5.25 || memcmp (c, " x", 2) != 0)
FAIL ();
const char *tmpdir = getenv ("TMPDIR");
if (tmpdir == NULL || tmpdir[0] == '\0')
tmpdir = "/tmp";
char fname[strlen (tmpdir) + sizeof "/tst-scanf14.XXXXXX"];
sprintf (fname, "%s/tst-scanf14.XXXXXX", tmpdir);
if (fname == NULL)
FAIL ();
/* Create a temporary file. */
int fd = mkstemp (fname);
if (fd == -1)
FAIL ();
FILE *fp = fdopen (fd, "w+");
if (fp == NULL)
FAIL ();
else
{
if (fputs (" 1.25s x", fp) == EOF)
FAIL ();
if (fseek (fp, 0, SEEK_SET) != 0)
FAIL ();
/* See explanation above. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
if (fscanf (fp, "%as%2c", &sp, c) != 2)
FAIL ();
else
{
if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
FAIL ();
memset (sp, 'x', sizeof "1.25s");
free (sp);
}
DIAG_POP_NEEDS_COMMENT;
if (freopen (fname, "r", stdin) == NULL)
FAIL ();
else
{
/* See explanation above. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
if (scanf ("%as%2c", &sp, c) != 2)
FAIL ();
else
{
if (strcmp (sp, "1.25s") != 0 || memcmp (c, " x", 2) != 0)
FAIL ();
memset (sp, 'x', sizeof "1.25s");
free (sp);
}
DIAG_POP_NEEDS_COMMENT;
}
fclose (fp);
}
remove (fname);
return result;
}