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[binutils.git] / libiberty / xstrerror.c
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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. */
5 /*
7 @deftypefn Replacement char* xstrerror (int @var{errnum})
9 Behaves exactly like the standard @code{strerror} function, but
10 will never return a @code{NULL} pointer.
12 @end deftypefn
16 #include <stdio.h>
18 #include "config.h"
19 #include "libiberty.h"
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
31 # endif /* __cplusplus */
32 # endif
33 #endif /* VMS */
36 #ifndef DONT_DECLARE_STRERROR
37 # ifdef __cplusplus
38 extern "C" {
39 # endif /* __cplusplus */
40 extern char *strerror (int);
41 # ifdef __cplusplus
43 # endif /* __cplusplus */
44 #endif
46 /* If strerror returns NULL, we'll format the number into a static buffer. */
48 #define ERRSTR_FMT "undocumented error #%d"
49 static char xstrerror_buf[sizeof ERRSTR_FMT + 20];
51 /* Like strerror, but result is never a null pointer. */
53 char *
54 xstrerror (int errnum)
56 char *errstr;
57 #ifdef VMS
58 char *(*vmslib_strerror) (int,...);
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
72 /* If `errnum' is out of range, result might be NULL. We'll fix that. */
73 if (!errstr)
75 sprintf (xstrerror_buf, ERRSTR_FMT, errnum);
76 errstr = xstrerror_buf;
78 return errstr;