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/* GNU variant of strerror_r. */

/*

FUNCTION

	<>---convert error number to string and copy to buffer

INDEX

	strerror_r

ANSI_SYNOPSIS

	#include 

	#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 

	char *strerror_r(<[errnum]>, <[buffer]>, <[n]>)

	int <[errnum]>;

	char *<[buffer]>;

	size_t <[n]>;

DESCRIPTION

<> 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 <>.  If <> is not a known

error number, the result is the empty string.

See <> for how strings are mapped to <>.

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 <> was not

recognized, and <[ERANGE]> if <[n]> was too small.  The variant chosen

depends on macros that you define before inclusion of <>.

PORTABILITY

<> with a <[char *]> result is a GNU extension.

<> 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 <> 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.

<> requires no supporting OS subroutines.

*/

#undef __STRICT_ANSI__

#define _GNU_SOURCE

#include 

#include 

#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);

}