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 }
80