1explain_pclose(3) Library Functions Manual explain_pclose(3)
2
6 explain_pclose - explain pclose(3) errors
7
9 #include <libexplain/pclose.h>
10 const char *explain_pclose(FILE *fp);
11 const char *explain_errno_pclose(int errnum, FILE *fp);
12 void explain_message_pclose(char *message, int message_size, FILE *fp);
13 void explain_message_errno_pclose(char *message, int message_size, int
14 errnum, FILE *fp);
15
17 These functions may be used to obtain explanations for errors returned
18 by the pclose(3) system call.
19 explain_pclose
21 const char *explain_pclose(FILE *fp);
22 The explain_pclose function is used to obtain an explanation of an
24 error returned by the pclose(3) system call. The least the message
25 will contain is the value of strerror(errno), but usually it will do
26 much better, and indicate the underlying cause in more detail.
27 The errno global variable will be used to obtain the error value to be
29 decoded.
30 This function is intended to be used in a fashion similar to the fol‐
32 lowing example:
33 if (pclose(fp) < 0)
34 {
35 fprintf(stderr, "%s\n", explain_pclose(fp));
36 exit(EXIT_FAILURE);
37 }
38 The above code example is available pre‐packaged as the
40 explain_pclose_or_die(3) function.
41 fp The original fp, exactly as passed to the pclose(3) system
43 call.
44 Returns:
46 The message explaining the error. This message buffer is
47 shared by all libexplain functions which do not supply a buffer
48 in their argument list. This will be overwritten by the next
49 call to any libexplain function which shares this buffer,
50 including other threads.
51 Note: This function is not thread safe, because it shares a return buf‐
53 fer across all threads, and many other functions in this library.
54 explain_errno_pclose
56 const char *explain_errno_pclose(int errnum, FILE *fp);
57 The explain_errno_pclose function is used to obtain an explanation of
59 an error returned by the pclose(3) system call. The least the message
60 will contain is the value of strerror(errnum), but usually it will do
61 much better, and indicate the underlying cause in more detail.
62 This function is intended to be used in a fashion similar to the fol‐
64 lowing example:
65 if (pclose(fp) < 0)
66 {
67 int err = errno;
68 fprintf(stderr, "%s\n", explain_errno_pclose(err, fp));
69 exit(EXIT_FAILURE);
70 }
71 The above code example is available pre‐packaged as the
73 explain_pclose_or_die(3) function.
74 errnum The error value to be decoded, usually obtained from the errno
76 global variable just before this function is called. This is
77 necessary if you need to call any code between the system call
78 to be explained and this function, because many libc functions
79 will alter the value of errno.
80 fp The original fp, exactly as passed to the pclose(3) system
82 call.
83 Returns:
85 The message explaining the error. This message buffer is
86 shared by all libexplain functions which do not supply a buffer
87 in their argument list. This will be overwritten by the next
88 call to any libexplain function which shares this buffer,
89 including other threads.
90 Note: This function is not thread safe, because it shares a return buf‐
92 fer across all threads, and many other functions in this library.
93 explain_message_pclose
95 void explain_message_pclose(char *message, int message_size, FILE *fp);
96 The explain_message_pclose function may be used to obtain an explana‐
98 tion of an error returned by the pclose(3) system call. The least the
99 message will contain is the value of strerror(errno), but usually it
100 will do much better, and indicate the underlying cause in more detail.
101 The errno global variable will be used to obtain the error value to be
103 decoded.
104 This function is intended to be used in a fashion similar to the fol‐
106 lowing example:
107 if (pclose(fp) < 0)
108 {
109 char message[3000];
110 explain_message_pclose(message, sizeof(message), fp);
111 fprintf(stderr, "%s\n", message);
112 exit(EXIT_FAILURE);
113 }
114 The above code example is available pre‐packaged as the
116 explain_pclose_or_die(3) function.
117 message The location in which to store the returned message. If a
119 suitable message return buffer is supplied, this function is
120 thread safe.
121 message_size
123 The size in bytes of the location in which to store the
124 returned message.
125 fp The original fp, exactly as passed to the pclose(3) system
127 call.
128 explain_message_errno_pclose
130 void explain_message_errno_pclose(char *message, int message_size, int
131 errnum, FILE *fp);
132 The explain_message_errno_pclose function may be used to obtain an
134 explanation of an error returned by the pclose(3) system call. The
135 least the message will contain is the value of strerror(errnum), but
136 usually it will do much better, and indicate the underlying cause in
137 more detail.
138 This function is intended to be used in a fashion similar to the fol‐
140 lowing example:
141 if (pclose(fp) < 0)
142 {
143 int err = errno;
144 char message[3000];
145 explain_message_errno_pclose(message, sizeof(message), err, fp);
146 fprintf(stderr, "%s\n", message);
147 exit(EXIT_FAILURE);
148 }
149 The above code example is available pre‐packaged as the
151 explain_pclose_or_die(3) function.
152 message The location in which to store the returned message. If a
154 suitable message return buffer is supplied, this function is
155 thread safe.
156 message_size
158 The size in bytes of the location in which to store the
159 returned message.
160 errnum The error value to be decoded, usually obtained from the errno
162 global variable just before this function is called. This is
163 necessary if you need to call any code between the system call
164 to be explained and this function, because many libc functions
165 will alter the value of errno.
166 fp The original fp, exactly as passed to the pclose(3) system
168 call.
169
171 pclose(3)
172 process I/O
173 explain_pclose_or_die(3)
175 process I/O and report errors
176
178 libexplain version 1.4
179 Copyright (C) 2009 Peter Miller
180 explain_pclose(3)