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  
       9  Behaves exactly like the standard @code{strerror} function, but
      10  will 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
      25  extern "C" {
      26  #    endif /* __cplusplus */
      27  extern 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
      38  extern "C" {
      39  #  endif /* __cplusplus */
      40  extern 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"
      49  static char xstrerror_buf[sizeof ERRSTR_FMT + 20];
      50  
      51  /* Like strerror, but result is never a null pointer.  */
      52  
      53  char *
      54  xstrerror (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  }