| /* GNU variant of strerror_r. */ |
| /* |
| FUNCTION |
| <<strerror_r>>---convert error number to string and copy to buffer |
| |
| INDEX |
| strerror_r |
| |
| ANSI_SYNOPSIS |
| #include <string.h> |
| #ifdef _GNU_SOURCE |
| char *strerror_r(int <[errnum]>, char *<[buffer]>, size_t <[n]>); |
| #else |
| int strerror_r(int <[errnum]>, char *<[buffer]>, size_t <[n]>); |
| #endif |
| |
| TRAD_SYNOPSIS |
| #include <string.h> |
| char *strerror_r(<[errnum]>, <[buffer]>, <[n]>) |
| int <[errnum]>; |
| char *<[buffer]>; |
| size_t <[n]>; |
| |
| DESCRIPTION |
| <<strerror_r>> converts the error number <[errnum]> into a |
| string and copies the result into the supplied <[buffer]> for |
| a length up to <[n]>, including the NUL terminator. The value of |
| <[errnum]> is usually a copy of <<errno>>. If <<errnum>> is not a known |
| error number, the result is the empty string. |
| |
| See <<strerror>> for how strings are mapped to <<errnum>>. |
| |
| RETURNS |
| There are two variants: the GNU version always returns a NUL-terminated |
| string, which is <[buffer]> if all went well, but which is another |
| pointer if <[n]> was too small (leaving <[buffer]> untouched). If the |
| return is not <[buffer]>, your application must not modify that string. |
| The POSIX version returns 0 on success, <[EINVAL]> if <<errnum>> was not |
| recognized, and <[ERANGE]> if <[n]> was too small. The variant chosen |
| depends on macros that you define before inclusion of <<string.h>>. |
| |
| PORTABILITY |
| <<strerror_r>> with a <[char *]> result is a GNU extension. |
| <<strerror_r>> with an <[int]> result is required by POSIX 2001. |
| This function is compliant only if <<_user_strerror>> is not provided, |
| or if it is thread-safe and uses separate storage according to whether |
| the second argument of that function is non-zero. For more details |
| on <<_user_strerror>>, see the <<strerror>> documentation. |
| |
| POSIX states that the contents of <[buf]> are unspecified on error, |
| although this implementation guarantees a NUL-terminated string for |
| all except <[n]> of 0. |
| |
| POSIX recommends that unknown <[errnum]> result in a message including |
| that value, however it is not a requirement and this implementation |
| provides only an empty string (unless you provide <<_user_strerror>>). |
| POSIX also recommends that unknown <[errnum]> fail with EINVAL even |
| when providing such a message, however it is not a requirement and |
| this implementation will return success if <<_user_strerror>> provided |
| a non-empty alternate string without assigning into its third argument. |
| |
| <<strerror_r>> requires no supporting OS subroutines. |
| |
| */ |
| |
| #undef __STRICT_ANSI__ |
| #define _GNU_SOURCE |
| #include <errno.h> |
| #include <string.h> |
| #undef strerror_r |
| |
| /* For backwards-compatible linking, this must be the GNU signature; |
| see xpg_strerror_r.c for the POSIX version. */ |
| char * |
| _DEFUN (strerror_r, (errnum, buffer, n), |
| int errnum _AND |
| char *buffer _AND |
| size_t n) |
| { |
| char *error = _strerror_r (_REENT, errnum, 1, NULL); |
| |
| if (strlen (error) >= n) |
| return error; |
| return strcpy (buffer, error); |
| } |