xstrerror.c
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/* xstrerror.c -- jacket routine for more robust strerror() usage.
Fri Jun 16 18:30:00 1995 Pat Rankin <rankin@eql.caltech.edu>
This code is in the public domain. */
/*
@deftypefn Replacement char* xstrerror (int @var{errnum})
Behaves exactly like the standard @code{strerror} function, but
will never return a @code{NULL} pointer.
@end deftypefn
*/
#include <stdio.h>
#include "libiberty.h"
#include "config.h"
#ifdef VMS
#include <errno.h>
#if !defined (__STRICT_ANSI__) && !defined (__HIDE_FORBIDDEN_NAMES)
extern char *strerror PARAMS ((int,...));
#define DONT_DECLARE_STRERROR
#endif
#endif /* VMS */
#ifndef DONT_DECLARE_STRERROR
extern char *strerror PARAMS ((int));
#endif
/* If strerror returns NULL, we'll format the number into a static buffer. */
#define ERRSTR_FMT "undocumented error #%d"
static char xstrerror_buf[sizeof ERRSTR_FMT + 20];
/* Like strerror, but result is never a null pointer. */
char *
xstrerror (errnum)
int errnum;
{
char *errstr;
#ifdef VMS
char *(*vmslib_strerror) PARAMS ((int,...));
/* Override any possibly-conflicting declaration from system header. */
vmslib_strerror = (char *(*) PARAMS ((int,...))) strerror;
/* Second argument matters iff first is EVMSERR, but it's simpler to
pass it unconditionally. `vaxc$errno' is declared in <errno.h>
and maintained by the run-time library in parallel to `errno'.
We assume that `errnum' corresponds to the last value assigned to
errno by the run-time library, hence vaxc$errno will be relevant. */
errstr = (*vmslib_strerror) (errnum, vaxc$errno);
#else
errstr = strerror (errnum);
#endif
/* If `errnum' is out of range, result might be NULL. We'll fix that. */
if (!errstr)
{
sprintf (xstrerror_buf, ERRSTR_FMT, errnum);
errstr = xstrerror_buf;
}
return errstr;
}