1/* xstrerror.c -- jacket routine for more robust strerror() usage. 2 Fri Jun 16 18:30:00 1995 Pat Rankin <rankin@eql.caltech.edu> 3 This code is in the public domain. */ 4 5/* 6 7@deftypefn Replacement char* xstrerror (int @var{errnum}) 8 9Behaves exactly like the standard @code{strerror} function, but 10will never return a @code{NULL} pointer. 11 12@end deftypefn 13 14*/ 15 16#include <stdio.h> 17 18#include "libiberty.h" 19#include "config.h" 20 21#ifdef VMS 22#include <errno.h> 23#if !defined (__STRICT_ANSI__) && !defined (__HIDE_FORBIDDEN_NAMES) 24extern char *strerror PARAMS ((int,...)); 25#define DONT_DECLARE_STRERROR 26#endif 27#endif /* VMS */ 28 29#ifndef DONT_DECLARE_STRERROR 30extern char *strerror PARAMS ((int)); 31#endif 32 33/* If strerror returns NULL, we'll format the number into a static buffer. */ 34 35#define ERRSTR_FMT "undocumented error #%d" 36static char xstrerror_buf[sizeof ERRSTR_FMT + 20]; 37 38/* Like strerror, but result is never a null pointer. */ 39 40char * 41xstrerror (errnum) 42 int errnum; 43{ 44 char *errstr; 45#ifdef VMS 46 char *(*vmslib_strerror) PARAMS ((int,...)); 47 48 /* Override any possibly-conflicting declaration from system header. */ 49 vmslib_strerror = (char *(*) PARAMS ((int,...))) strerror; 50 /* Second argument matters iff first is EVMSERR, but it's simpler to 51 pass it unconditionally. `vaxc$errno' is declared in <errno.h> 52 and maintained by the run-time library in parallel to `errno'. 53 We assume that `errnum' corresponds to the last value assigned to 54 errno by the run-time library, hence vaxc$errno will be relevant. */ 55 errstr = (*vmslib_strerror) (errnum, vaxc$errno); 56#else 57 errstr = strerror (errnum); 58#endif 59 60 /* If `errnum' is out of range, result might be NULL. We'll fix that. */ 61 if (!errstr) 62 { 63 sprintf (xstrerror_buf, ERRSTR_FMT, errnum); 64 errstr = xstrerror_buf; 65 } 66 return errstr; 67} 68