https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96916
Bug ID: 96916
Summary: warning: ‘strndup’ specified bound
18446744073709551615 exceeds maximum object size
9223372036854775807 [-Wstringop-overflow=]
Product: gcc
Version: 10.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: rjones at redhat dot com
Target Milestone: ---
I'm not certain this is really a bug, but I don't understand it. A simple
reproducer:
----------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
const char *
copyn (const char *str, size_t n)
{
return strndup (str, n);
}
const char *
copy (const char *str)
{
return copyn (str, SIZE_MAX);
}
----------------------------------------------------------------------
$ gcc -O2 -Wall -c test.c
In function ‘copyn’,
inlined from ‘copy’ at test.c:15:10:
test.c:9:10: warning: ‘strndup’ specified bound 18446744073709551615 exceeds
maximum object size 9223372036854775807 [-Wstringop-overflow=]
9 | return strndup (str, n);
| ^~~~~~~~~~~~~~~~
$ gcc --version
gcc (GCC) 10.2.1 20200826 (Red Hat 10.2.1-3)
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Note that it seems as if the compiler is claiming that strndup cannot cope with
a string larger than ssize_t (rather than size_t), which is unexpected.
