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

6       explain_setvbuf - explain setvbuf(3) errors
7

SYNOPSIS

9       #include <libexplain/setvbuf.h>
10       const char *explain_setvbuf(FILE *fp, char *data, int mode, size_t
11       size);
12       const char *explain_errno_setvbuf(int errnum, FILE *fp, char *data, int
13       mode, size_t size);
14       void explain_message_setvbuf(char *message, int message_size, FILE *fp,
15       char *data, int mode, size_t size);
16       void explain_message_errno_setvbuf(char *message, int message_size, int
17       errnum, FILE *fp, char *data, int mode, size_t size);
18

DESCRIPTION

20       These  functions may be used to obtain explanations for errors returned
21       by the setvbuf(3) system call.
22
23   explain_setvbuf
24       const char *explain_setvbuf(FILE *fp, char *data, int mode, size_t
25       size);
26
27       The  explain_setvbuf  function  is  used to obtain an explanation of an
28       error returned by the setvbuf(3) system call.  The  least  the  message
29       will  contain  is  the value of strerror(errno), but usually it will do
30       much better, and indicate the underlying cause in more detail.
31
32       The errno global variable will be used to obtain the error value to  be
33       decoded.
34
35       fp      The  original  fp,  exactly  as passed to the setvbuf(3) system
36               call.
37
38       data    The original data, exactly as passed to the  setvbuf(3)  system
39               call.
40
41       mode    The  original  mode, exactly as passed to the setvbuf(3) system
42               call.
43
44       size    The original size, exactly as passed to the  setvbuf(3)  system
45               call.
46
47       Returns:
48               The message explaining the error. This message buffer is shared
49               by all libexplain functions which do not  supply  a  buffer  in
50               their argument list.  This will be overwritten by the next call
51               to any libexplain function which shares this buffer,  including
52               other threads.
53
54       Note: This function is not thread safe, because it shares a return buf‐
55       fer across all threads, and many other functions in this library.
56
57       Example: This function is intended to be used in a fashion  similar  to
58       the following example:
59              if (setvbuf(fp, data, mode, size) < 0)
60              {
61                  fprintf(stderr, "%s\n", explain_setvbuf(fp, data, mode,
62                  size));
63                  exit(EXIT_FAILURE);
64              }
65
66       The   above   code   example   is   available   pre‐packaged   as   the
67       explain_setvbuf_or_die(3) function.
68
69   explain_errno_setvbuf
70       const char *explain_errno_setvbuf(int errnum, FILE *fp, char *data, int
71       mode, size_t size);
72
73       The explain_errno_setvbuf function is used to obtain an explanation  of
74       an  error returned by the setvbuf(3) system call. The least the message
75       will contain is the value of strerror(errno), but usually  it  will  do
76       much better, and indicate the underlying cause in more detail.
77
78       errnum  The  error value to be decoded, usually obtained from the errno
79               global variable just before this function is  called.  This  is
80               necessary  if you need to call any code between the system call
81               to be explained and this function, because many libc  functions
82               will alter the value of errno.
83
84       fp      The  original  fp,  exactly  as passed to the setvbuf(3) system
85               call.
86
87       data    The original data, exactly as passed to the  setvbuf(3)  system
88               call.
89
90       mode    The  original  mode, exactly as passed to the setvbuf(3) system
91               call.
92
93       size    The original size, exactly as passed to the  setvbuf(3)  system
94               call.
95
96       Returns:
97               The message explaining the error. This message buffer is shared
98               by all libexplain functions which do not  supply  a  buffer  in
99               their argument list.  This will be overwritten by the next call
100               to any libexplain function which shares this buffer,  including
101               other threads.
102
103       Note: This function is not thread safe, because it shares a return buf‐
104       fer across all threads, and many other functions in this library.
105
106       Example: This function is intended to be used in a fashion  similar  to
107       the following example:
108              if (setvbuf(fp, data, mode, size) < 0)
109              {
110                  int err = errno;
111                  fprintf(stderr, "%s\n", explain_errno_setvbuf(err, fp, data,
112                  mode, size));
113                  exit(EXIT_FAILURE);
114              }
115
116       The   above   code   example   is   available   pre‐packaged   as   the
117       explain_setvbuf_or_die(3) function.
118
119   explain_message_setvbuf
120       void explain_message_setvbuf(char *message, int message_size, FILE *fp,
121       char *data, int mode, size_t size);
122
123       The explain_message_setvbuf function is used to obtain  an  explanation
124       of  an error returned by the setvbuf(3) system call. The least the mes‐
125       sage will contain is the value of strerror(errno), but usually it  will
126       do much better, and indicate the underlying cause in more detail.
127
128       The  errno global variable will be used to obtain the error value to be
129       decoded.
130
131       message The location in which to store the returned message. If a suit‐
132               able message return buffer is supplied, this function is thread
133               safe.
134
135       message_size
136               The size in bytes  of  the  location  in  which  to  store  the
137               returned message.
138
139       fp      The  original  fp,  exactly  as passed to the setvbuf(3) system
140               call.
141
142       data    The original data, exactly as passed to the  setvbuf(3)  system
143               call.
144
145       mode    The  original  mode, exactly as passed to the setvbuf(3) system
146               call.
147
148       size    The original size, exactly as passed to the  setvbuf(3)  system
149               call.
150
151       Example:  This  function is intended to be used in a fashion similar to
152       the following example:
153              if (setvbuf(fp, data, mode, size) < 0)
154              {
155                  char message[3000];
156                  explain_message_setvbuf(message, sizeof(message), fp, data,
157                  mode, size);
158                  fprintf(stderr, "%s\n", message);
159                  exit(EXIT_FAILURE);
160              }
161
162       The   above   code   example   is   available   pre‐packaged   as   the
163       explain_setvbuf_or_die(3) function.
164
165   explain_message_errno_setvbuf
166       void explain_message_errno_setvbuf(char *message, int message_size, int
167       errnum, FILE *fp, char *data, int mode, size_t size);
168
169       The  explain_message_errno_setvbuf function is used to obtain an expla‐
170       nation of an error returned by the setvbuf(3) system  call.  The  least
171       the  message  will contain is the value of strerror(errno), but usually
172       it will do much better, and  indicate  the  underlying  cause  in  more
173       detail.
174
175       message The location in which to store the returned message. If a suit‐
176               able message return buffer is supplied, this function is thread
177               safe.
178
179       message_size
180               The  size  in  bytes  of  the  location  in  which to store the
181               returned message.
182
183       errnum  The error value to be decoded, usually obtained from the  errno
184               global  variable  just  before this function is called. This is
185               necessary if you need to call any code between the system  call
186               to  be explained and this function, because many libc functions
187               will alter the value of errno.
188
189       fp      The original fp, exactly as passed  to  the  setvbuf(3)  system
190               call.
191
192       data    The  original  data, exactly as passed to the setvbuf(3) system
193               call.
194
195       mode    The original mode, exactly as passed to the  setvbuf(3)  system
196               call.
197
198       size    The  original  size, exactly as passed to the setvbuf(3) system
199               call.
200
201       Example: This function is intended to be used in a fashion  similar  to
202       the following example:
203              if (setvbuf(fp, data, mode, size) < 0)
204              {
205                  int err = errno;
206                  char message[3000];
207                  explain_message_errno_setvbuf(message, sizeof(message), err,
208                  fp, data, mode, size);
209                  fprintf(stderr, "%s\n", message);
210                  exit(EXIT_FAILURE);
211              }
212
213       The   above   code   example   is   available   pre‐packaged   as   the
214       explain_setvbuf_or_die(3) function.
215

SEE ALSO

217       setvbuf(3)
218               stream buffering operations
219
220       explain_setvbuf_or_die(3)
221               stream buffering operations and report errors
222
224       libexplain version 0.40
225       Copyright (C) 2010 Peter Miller
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229                                                            explain_setvbuf(3)
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