/**
* slibc — Yet another C library
* Copyright © 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include <stddef.h>
/**
* Return a textual representation of an error code.
* This error code must from `errno`.
*
* This implementation of `strerror` cannot fail. however
* POSIX specifies that it can fail, any may only set `errno`
* if it does fail. You should therefore, set `errno` to
* zero before calling this function, and inspect `errno`
* when it returns, as there is no reserved return value
* that indicates and error.
*
* The returned value must not be modified or freed.
*
* As a slibc-specific modification, this function is MT-Safe.
*
* @param errnum The error code.
* @return A description of the error.
*/
char* strerror(int errnum)
{
return strerror_l(errnum, CURRENT_LOCALE /* TODO not defined */);
}
/**
* Return a textual representation of an error code.
* This error code must from `errno`.
*
* POSIX specifies `errno` may only be set on failure,
* and reserves no return value to indicate such.
* You should therefore, set `errno` to zero before calling
* this function, and inspect `errno` when it returns.
*
* The returned value must not be modified or freed.
*
* @param errnum The error code.
* @param locale The locale, must be a valid locale and not
* `LC_GLOBAL_LOCALE`, lest the behaviour is undefined.
* @return A description of the error.
*/
char* strerror_l(int errnum, locale_t locale)
{
/* TODO implement strerror_l */
return (void) errnum, (void) locale, NULL:
}
/**
* Reenterant variant of `strerror`.
*
* This is an XSI-compliant extension. However the name
* is not part of the XSI specification, `strerror_r`
* should be used. It is defined to this function if
* `(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !_GNU_SOURCE`.
* However it is not defined if _SLIBC_SOURCE is defined.
*
* @param errnum The error code.
* @param buf Buffer where the description shall be stored.
* @param buflen The allocation size of `buf`.
* @return Zero on success, value for `errno` on error
*
* @throws ERANGE `buf` was too small to store the description.
*/
int __xsi_strerror_r(int errnum, char* buf, size_t buflen)
{
char* description = strerror(errnum);
size_t length = strlen(description);
if (buflen == 0)
return ERANGE;
if (buflen <= length)
{
memcpy(buf, description, buflen - 1);
buf[buflen - 1] = 0;
return ERANGE;
}
return memcpy(buf, description, length + 1), 0;
}
/**
* Reenterant variant of `strerror`.
*
* This is a GNU-specific extension. However the name
* is not part of the GNU specification, `strerror_r` should
* be used. It is defined to this function unless
* `(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600) && !_GNU_SOURCE`.
* However it is not defined if _SLIBC_SOURCE is defined.
*
* @param errnum The error code.
* @param buf Buffer where the description shall be stored.
* @param buflen The allocation size of `buf`.
* @return `buf` on success, `NULL` on error. On error, `errno`
* is set to indicate the error.
*
* @throws ERANGE `buf` was too small to store the description.
*/
char* __gnu_strerror_r(int errnum, char* buf, size_t buflen)
{
errno = __xsi_strerror_r(errnum, buf, buflen);
return errno ? NULL : buf;
}
