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From: "sworddragon2 at aol dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/55896] New: Annoying compiler warning
Date: Mon, 07 Jan 2013 13:48:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55896

             Bug #: 55896
           Summary: Annoying compiler warning
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: sworddragon2@aol.com


Created attachment 29097
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29097
Example code

After changing a global struct to a static variable I got a compiler warning. I
have analyzed this and tried to produce a minimum testcase. In the attachments
is an example code and compiling it with "gcc -O3 -Wall -Wextra -o test
-pedantic test.c" will result in the following warning:

In file included from /usr/include/string.h:638:0,
                 from test.c:3:
In function 'strncat',
    inlined from 'load_app_settings' at test.c:39:10:
/usr/include/x86_64-linux-gnu/bits/string3.h:150:3: warning: call to
__builtin___strncat_chk might overflow destination buffer [enabled by default]

Removing static from "static struct status STATUS;" solves the problem. Any
random change in load_app_settings() can solve the problem too even if the
change has nothing to do with the problem. For example if "strncat(content_2,
content_1, w_strlen(content_1) - 1);" is changed to "strncat(content_2,
content_1, w_strlen(content_1));" or " && content_1[0] == '['" is removed in
the condition.