1*a9fa9459Szrj /* xstrerror.c -- jacket routine for more robust strerror() usage.
2*a9fa9459Szrj Fri Jun 16 18:30:00 1995 Pat Rankin <rankin@eql.caltech.edu>
3*a9fa9459Szrj This code is in the public domain. */
4*a9fa9459Szrj
5*a9fa9459Szrj /*
6*a9fa9459Szrj
7*a9fa9459Szrj @deftypefn Replacement char* xstrerror (int @var{errnum})
8*a9fa9459Szrj
9*a9fa9459Szrj Behaves exactly like the standard @code{strerror} function, but
10*a9fa9459Szrj will never return a @code{NULL} pointer.
11*a9fa9459Szrj
12*a9fa9459Szrj @end deftypefn
13*a9fa9459Szrj
14*a9fa9459Szrj */
15*a9fa9459Szrj
16*a9fa9459Szrj #include <stdio.h>
17*a9fa9459Szrj
18*a9fa9459Szrj #include "config.h"
19*a9fa9459Szrj #include "libiberty.h"
20*a9fa9459Szrj
21*a9fa9459Szrj #ifdef VMS
22*a9fa9459Szrj # include <errno.h>
23*a9fa9459Szrj # if !defined (__STRICT_ANSI__) && !defined (__HIDE_FORBIDDEN_NAMES)
24*a9fa9459Szrj # ifdef __cplusplus
25*a9fa9459Szrj extern "C" {
26*a9fa9459Szrj # endif /* __cplusplus */
27*a9fa9459Szrj extern char *strerror (int,...);
28*a9fa9459Szrj # define DONT_DECLARE_STRERROR
29*a9fa9459Szrj # ifdef __cplusplus
30*a9fa9459Szrj }
31*a9fa9459Szrj # endif /* __cplusplus */
32*a9fa9459Szrj # endif
33*a9fa9459Szrj #endif /* VMS */
34*a9fa9459Szrj
35*a9fa9459Szrj
36*a9fa9459Szrj #ifndef DONT_DECLARE_STRERROR
37*a9fa9459Szrj # ifdef __cplusplus
38*a9fa9459Szrj extern "C" {
39*a9fa9459Szrj # endif /* __cplusplus */
40*a9fa9459Szrj extern char *strerror (int);
41*a9fa9459Szrj # ifdef __cplusplus
42*a9fa9459Szrj }
43*a9fa9459Szrj # endif /* __cplusplus */
44*a9fa9459Szrj #endif
45*a9fa9459Szrj
46*a9fa9459Szrj /* If strerror returns NULL, we'll format the number into a static buffer. */
47*a9fa9459Szrj
48*a9fa9459Szrj #define ERRSTR_FMT "undocumented error #%d"
49*a9fa9459Szrj static char xstrerror_buf[sizeof ERRSTR_FMT + 20];
50*a9fa9459Szrj
51*a9fa9459Szrj /* Like strerror, but result is never a null pointer. */
52*a9fa9459Szrj
53*a9fa9459Szrj char *
xstrerror(int errnum)54*a9fa9459Szrj xstrerror (int errnum)
55*a9fa9459Szrj {
56*a9fa9459Szrj char *errstr;
57*a9fa9459Szrj #ifdef VMS
58*a9fa9459Szrj char *(*vmslib_strerror) (int,...);
59*a9fa9459Szrj
60*a9fa9459Szrj /* Override any possibly-conflicting declaration from system header. */
61*a9fa9459Szrj vmslib_strerror = (char *(*) (int,...)) strerror;
62*a9fa9459Szrj /* Second argument matters iff first is EVMSERR, but it's simpler to
63*a9fa9459Szrj pass it unconditionally. `vaxc$errno' is declared in <errno.h>
64*a9fa9459Szrj and maintained by the run-time library in parallel to `errno'.
65*a9fa9459Szrj We assume that `errnum' corresponds to the last value assigned to
66*a9fa9459Szrj errno by the run-time library, hence vaxc$errno will be relevant. */
67*a9fa9459Szrj errstr = (*vmslib_strerror) (errnum, vaxc$errno);
68*a9fa9459Szrj #else
69*a9fa9459Szrj errstr = strerror (errnum);
70*a9fa9459Szrj #endif
71*a9fa9459Szrj
72*a9fa9459Szrj /* If `errnum' is out of range, result might be NULL. We'll fix that. */
73*a9fa9459Szrj if (!errstr)
74*a9fa9459Szrj {
75*a9fa9459Szrj sprintf (xstrerror_buf, ERRSTR_FMT, errnum);
76*a9fa9459Szrj errstr = xstrerror_buf;
77*a9fa9459Szrj }
78*a9fa9459Szrj return errstr;
79*a9fa9459Szrj }
80