1explain_chdir(3)           Library Functions Manual           explain_chdir(3)
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NAME

6       explain_chdir - explain chdir(2) errors
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SYNOPSIS

9       #include <libexplain/chdir.h>
10       const char *explain_chdir(const char *pathname);
11       void  explain_message_chdir(char *message, int message_size, const char
12       *pathname);
13       const char *explain_errno_chdir(int errnum, const char *pathname);
14       void explain_message_errno_chdir(char *message, int  message_size,  int
15       errnum, const char *pathname);
16

DESCRIPTION

18       These function may be used to obtain explanations of chdir(2) errors.
19
20   explain_chdir
21       const char *explain_chdir(const char *pathname);
22
23       The explain_chdir function is used to obtain an explanation of an error
24       returned by the chdir(2) system call.  The least the message will  con‐
25       tain  is the value of strerror(errno), but usually it will do much bet‐
26       ter, and indicate the underlying cause in more detail.
27
28       The errno global variable will be used to obtain the error value to  be
29       decoded.
30
31       This  function  is intended to be used in a fashion similar to the fol‐
32       lowing example:
33              if (chdir(pathname) < 0)
34              {
35                  fprintf(stderr, '%s0, explain_chdir(pathname));
36                  exit(EXIT_FAILURE);
37              }
38
39       pathname
40               The original pathname, exactly as passed to the chdir(2) system
41               call.
42
43       Returns:
44               The  message  explaining  the  error.   This  message buffer is
45               shared by all libexplain functions which do not supply a buffer
46               in  their  argument list.  This will be overwritten by the next
47               call to any  libexplain  function  which  shares  this  buffer,
48               including other threads.
49
50       Note: This function is not thread safe, because it shares a return buf‐
51       fer across all threads, and many other functions in this library.
52
53   explain_errno_chdir
54       const char *explain_errno_chdir(int errnum, const char *pathname);
55
56       The explain_errno_chdir function is used to obtain an explanation of an
57       error returned by the chdir(2) system call.  The least the message will
58       contain is the value of strerror(errnum), but usually it will  do  much
59       better, and indicate the underlying cause in more detail.
60
61       This  function  is intended to be used in a fashion similar to the fol‐
62       lowing example:
63              if (chdir(pathname) < 0)
64              {
65                  int err = errno;
66                  fprintf(stderr, '%s0, explain_errno_chdir(err, pathname));
67                  exit(EXIT_FAILURE);
68              }
69
70       errnum  The error value to be decoded, usually obtained from the  errno
71               global  variable  just before this function is called.  This is
72               necessary if you need to call any code between the system  call
73               to  be explained and this function, because many libc functions
74               will alter the value of errno.
75
76       pathname
77               The original pathname, exactly as passed to the chdir(2) system
78               call.
79
80       Returns:
81               The  message  explaining  the  error.   This  message buffer is
82               shared by all libexplain functions which do not supply a buffer
83               in  their  argument list.  This will be overwritten by the next
84               call to any  libexplain  function  which  shares  this  buffer,
85               including other threads.
86
87       Note: This function is not thread safe, because it shares a return buf‐
88       fer across all threads, and many other functions in this library.
89
90   explain_message_chdir
91       void explain_message_chdir(char *message, int message_size, const  char
92       *pathname);
93
94       The  explain_message_chdir function is used to obtain an explanation of
95       an error returned by the chdir(2) system call.  The least  the  message
96       will  contain  is  the value of strerror(errno), but usually it will do
97       much better, and indicate the underlying cause in more detail.
98
99       The errno global variable will be used to obtain the error value to  be
100       decoded.
101
102       This  function  is intended to be used in a fashion similar to the fol‐
103       lowing example:
104              if (chdir(pathname) < 0)
105              {
106                  char message[3000];
107                  explain_message_chdir(message, sizeof(message), pathname);
108                  fprintf(stderr, '%s0, message);
109                  exit(EXIT_FAILURE);
110              }
111
112       message The location in which to store the returned message.  Because a
113               message  return  buffer  has  been  supplied,  this function is
114               thread safe.
115
116       message_size
117               The size in bytes  of  the  location  in  which  to  store  the
118               returned message.
119
120       pathname
121               The original pathname, exactly as passed to the chdir(2) system
122               call.
123
124   explain_message_errno_chdir
125       void explain_message_errno_chdir(char *message, int  message_size,  int
126       errnum, const char * pathname);
127
128       The  explain_message_errno_chdir function is used to obtain an explana‐
129       tion of an error returned by the chdir(2) system call.  The  least  the
130       message  will  contain is the value of strerror(errnum), but usually it
131       will do much better, and indicate the underlying cause in more detail.
132
133       This function is intended to be used in a fashion similar to  the  fol‐
134       lowing example:
135              if (chdir(pathname) < 0)
136              {
137                  int err = errno;
138                  char message[3000];
139                  explain_message_errno_chdir(message, sizeof(message), err,
140                      pathname);
141                  fprintf(stderr, '%s0, message);
142                  exit(EXIT_FAILURE);
143              }
144
145       message The location in which to store the returned message.  Because a
146               message return buffer  has  been  supplied,  this  function  is
147               thread safe.
148
149       message_size
150               The  size  in  bytes  of  the  location  in  which to store the
151               returned message.
152
153       errnum  The error value to be decoded, usually obtained from the  errno
154               global  variable  just before this function is called.  This is
155               necessary if you need to call any code between the system  call
156               to  be explained and this function, because many libc functions
157               will alter the value of errno.
158
159       pathname
160               The original pathname, exactly as passed to the chdir(2) system
161               call.
162
164       libexplain version 0.40
165       Copyright (C) 2008 Peter Miller
166

AUTHOR

168       Written by Peter Miller <pmiller@opensource.org.au>
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172                                                              explain_chdir(3)
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