newlib/libc/stdio/perror.c

   1 /*
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * and/or other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  */
  17
  18 /*
  19 FUNCTION
  20 <<perror>>---print an error message on standard error
  21
  22 INDEX
  23         perror
  24 INDEX
  25         _perror_r
  26
  27 SYNOPSIS
  28         #include <stdio.h>
  29         void perror(char *<[prefix]>);
  30
  31         void _perror_r(struct _reent *<[reent]>, char *<[prefix]>);
  32
  33 DESCRIPTION
  34 Use <<perror>> to print (on standard error) an error message
  35 corresponding to the current value of the global variable <<errno>>.
  36 Unless you use <<NULL>> as the value of the argument <[prefix]>, the
  37 error message will begin with the string at <[prefix]>, followed by a
  38 colon and a space (<<: >>). The remainder of the error message is one
  39 of the strings described for <<strerror>>.
  40
  41 The alternate function <<_perror_r>> is a reentrant version.  The
  42 extra argument <[reent]> is a pointer to a reentrancy structure.
  43
  44 RETURNS
  45 <<perror>> returns no result.
  46
  47 PORTABILITY
  48 ANSI C requires <<perror>>, but the strings issued vary from one
  49 implementation to another.
  50
  51 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
  52 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
  53 */
  54
  55 #include <_ansi.h>
  56 #include <reent.h>
  57 #include <stdio.h>
  58 #include <string.h>
  59 #include "local.h"
  60
  61 #define WRITE_STR(str) \
  62 { \
  63   const char *p = (str); \
  64   size_t len = strlen (p); \
  65   while (len) \
  66     { \
  67       ssize_t len1 = _write_r (ptr, fileno (fp), p, len); \
  68       if (len1 < 0) \
  69         break; \
  70       len -= len1; \
  71       p += len1; \
  72     } \
  73 }
  74
  75 void
  76 _perror_r (struct _reent *ptr,
  77        const char *s)
  78 {
  79   char *error;
  80   int dummy;
  81   FILE *fp = _stderr_r (ptr);
  82
  83   CHECK_INIT (ptr, fp);
  84
  85   _newlib_flockfile_start(fp);
  86   _fflush_r (ptr, fp);
  87   if (s != NULL && *s != '\0')
  88     {
  89       WRITE_STR (s);
  90       WRITE_STR (": ");
  91     }
  92
  93   if ((error = _strerror_r (ptr, _REENT_ERRNO(ptr), 1, &dummy)) != NULL)
  94     WRITE_STR (error);
  95
  96 #ifdef __SCLE
  97   WRITE_STR ((fp->_flags & __SCLE) ? "\r\n" : "\n");
  98 #else
  99   WRITE_STR ("\n");
 100 #endif
 101   fp->_flags &= ~__SOFF;
 102   _newlib_flockfile_end(fp);
 103 }
 104
 105 #ifndef _REENT_ONLY
 106
 107 void
 108 perror (const char *s)
 109 {
 110   _perror_r (_REENT, s);
 111 }
 112
 113 #endif