glibc/string/xpg-strerror.c

47 lines
1.5 KiB
C

/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/param.h>
/* Fill buf with a string describing the errno code in ERRNUM. */
int
__xpg_strerror_r (int errnum, char *buf, size_t buflen)
{
const char *estr = __strerror_r (errnum, buf, buflen);
/* We know that __strerror_r returns buf (with a dynamically computed
string) if errnum is invalid, otherwise it returns a string whose
storage has indefinite extent. */
if (estr == buf)
return EINVAL;
else
{
size_t estrlen = strlen (estr);
/* Terminate the string in any case. */
if (buflen > 0)
*((char *) __mempcpy (buf, estr, MIN (buflen - 1, estrlen))) = '\0';
return buflen <= estrlen ? ERANGE : 0;
}
}