xstrerror.c revision 1.1
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 "config.h" 19#include "libiberty.h" 20 21#ifdef VMS 22# include <errno.h> 23# if !defined (__STRICT_ANSI__) && !defined (__HIDE_FORBIDDEN_NAMES) 24# ifdef __cplusplus 25extern "C" { 26# endif /* __cplusplus */ 27extern char *strerror (int,...); 28# define DONT_DECLARE_STRERROR 29# ifdef __cplusplus 30} 31# endif /* __cplusplus */ 32# endif 33#endif /* VMS */ 34 35 36#ifndef DONT_DECLARE_STRERROR 37# ifdef __cplusplus 38extern "C" { 39# endif /* __cplusplus */ 40extern char *strerror (int); 41# ifdef __cplusplus 42} 43# endif /* __cplusplus */ 44#endif 45 46/* If strerror returns NULL, we'll format the number into a static buffer. */ 47 48#define ERRSTR_FMT "undocumented error #%d" 49static char xstrerror_buf[sizeof ERRSTR_FMT + 20]; 50 51/* Like strerror, but result is never a null pointer. */ 52 53char * 54xstrerror (int errnum) 55{ 56 char *errstr; 57#ifdef VMS 58 char *(*vmslib_strerror) (int,...); 59 60 /* Override any possibly-conflicting declaration from system header. */ 61 vmslib_strerror = (char *(*) (int,...)) strerror; 62 /* Second argument matters iff first is EVMSERR, but it's simpler to 63 pass it unconditionally. `vaxc$errno' is declared in <errno.h> 64 and maintained by the run-time library in parallel to `errno'. 65 We assume that `errnum' corresponds to the last value assigned to 66 errno by the run-time library, hence vaxc$errno will be relevant. */ 67 errstr = (*vmslib_strerror) (errnum, vaxc$errno); 68#else 69 errstr = strerror (errnum); 70#endif 71 72 /* If `errnum' is out of range, result might be NULL. We'll fix that. */ 73 if (!errstr) 74 { 75 sprintf (xstrerror_buf, ERRSTR_FMT, errnum); 76 errstr = xstrerror_buf; 77 } 78 return errstr; 79} 80