This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: Add macros for diagnostic control, use for scanf %a tests

From: Paul Eggert <eggert at cs dot ucla dot edu>
To: Joseph Myers <joseph at codesourcery dot com>, libc-alpha at sourceware dot org
Date: Tue, 25 Nov 2014 16:36:07 -0800
Subject: Re: Add macros for diagnostic control, use for scanf %a tests
Authentication-results: sourceware.org; auth=none
References: <alpine dot DEB dot 2 dot 10 dot 1411252243090 dot 17237 at digraph dot polyomino dot org dot uk>

Joseph Myers wrote:

+  /* 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
@@ -32,10 +40,14 @@ main (void)
        memset (sp, 'x', sizeof "1.25s");
        free (sp);
      }
+  DIAG_POP_NEEDS_COMMENT;

This sort of thing looks intrusive. Instead, how about defining a macro'C99_sscanf' that does the push and pop and commentary, and then simplyreplacing warned-about uses of sscanf with C99_scanf? That'd be a lot easier toread, and it's more along the lines of Roland's original suggestion.

Follow-Ups:
- Re: Add macros for diagnostic control, use for scanf %a tests
  - From: Joseph Myers

References:
- Add macros for diagnostic control, use for scanf %a tests
  - From: Joseph Myers

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]