1explain_fputc(3) Library Functions Manual explain_fputc(3)
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6 explain_fputc - explain fputc(3) errors
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9 #include <libexplain/fputc.h>
10 const char *explain_fputc(int c, FILE *fp);
11 const char *explain_errno_fputc(int errnum, int c, FILE *fp);
12 void explain_message_fputc(char *message, int message_size, int c, FILE
13 *fp);
14 void explain_message_errno_fputc(char *message, int message_size, int
15 errnum, int c, FILE *fp);
16
18 These functions may be used to obtain explanations for errors returned
19 by the fputc(3) system call.
20 explain_fputc
22 const char *explain_fputc(int c, FILE *fp);
23 The explain_fputc function is used to obtain an explanation of an error
25 returned by the fputc(3) system call. The least the message will con‐
26 tain is the value of strerror(errno), but usually it will do much bet‐
27 ter, and indicate the underlying cause in more detail.
28 The errno global variable will be used to obtain the error value to be
30 decoded.
31 This function is intended to be used in a fashion similar to the fol‐
33 lowing example:
34 if (fputc(c, fp) == EOF)
35 {
36 fprintf(stderr, "%s\n", explain_fputc(c, fp));
37 exit(EXIT_FAILURE);
38 }
39 c The original c, exactly as passed to the fputc(3) system call.
41 fp The original fp, exactly as passed to the fputc(3) system call.
43 Returns:
45 The message explaining the error. This message buffer is
46 shared by all libexplain functions which do not supply a buffer
47 in their argument list. This will be overwritten by the next
48 call to any libexplain function which shares this buffer,
49 including other threads.
50 Note: This function is not thread safe, because it shares a return buf‐
52 fer across all threads, and many other functions in this library.
53 explain_errno_fputc
55 const char *explain_errno_fputc(int errnum, int c, FILE *fp);
56 The explain_errno_fputc function is used to obtain an explanation of an
58 error returned by the fputc(3) system call. The least the message will
59 contain is the value of strerror(errnum), but usually it will do much
60 better, and indicate the underlying cause in more detail.
61 This function is intended to be used in a fashion similar to the fol‐
63 lowing example:
64 if (fputc(c, fp) == EOF)
65 {
66 int err = errno;
67 fprintf(stderr, "%s\n", explain_errno_fputc(err, c, fp));
68 exit(EXIT_FAILURE);
69 }
70 errnum The error value to be decoded, usually obtained from the errno
72 global variable just before this function is called. This is
73 necessary if you need to call any code between the system call
74 to be explained and this function, because many libc functions
75 will alter the value of errno.
76 c The original c, exactly as passed to the fputc(3) system call.
78 fp The original fp, exactly as passed to the fputc(3) system call.
80 Returns:
82 The message explaining the error. This message buffer is
83 shared by all libexplain functions which do not supply a buffer
84 in their argument list. This will be overwritten by the next
85 call to any libexplain function which shares this buffer,
86 including other threads.
87 Note: This function is not thread safe, because it shares a return buf‐
89 fer across all threads, and many other functions in this library.
90 explain_message_fputc
92 void explain_message_fputc(char *message, int message_size, int c, FILE
93 *fp);
94 The explain_message_fputc function may be used to obtain an explana‐
96 tion of an error returned by the fputc(3) system call. The least the
97 message will contain is the value of strerror(errno), but usually it
98 will do much better, and indicate the underlying cause in more detail.
99 The errno global variable will be used to obtain the error value to be
101 decoded.
102 This function is intended to be used in a fashion similar to the fol‐
104 lowing example:
105 if (fputc(c, fp) == EOF)
106 {
107 char message[3000];
108 explain_message_fputc(message, sizeof(message), c, fp);
109 fprintf(stderr, "%s\n", message);
110 exit(EXIT_FAILURE);
111 }
112 message The location in which to store the returned message. If a
114 suitable message return buffer is supplied, this function is
115 thread safe.
116 message_size
118 The size in bytes of the location in which to store the
119 returned message.
120 c The original c, exactly as passed to the fputc(3) system call.
122 fp The original fp, exactly as passed to the fputc(3) system call.
124 explain_message_errno_fputc
126 void explain_message_errno_fputc(char *message, int message_size, int
127 errnum, int c, FILE *fp);
128 The explain_message_errno_fputc function may be used to obtain an
130 explanation of an error returned by the fputc(3) system call. The
131 least the message will contain is the value of strerror(errnum), but
132 usually it will do much better, and indicate the underlying cause in
133 more detail.
134 This function is intended to be used in a fashion similar to the fol‐
136 lowing example:
137 if (fputc(c, fp) == EOF)
138 {
139 int err = errno;
140 char message[3000];
141 explain_message_errno_fputc(message, sizeof(message), err, c, fp);
142 fprintf(stderr, "%s\n", message);
143 exit(EXIT_FAILURE);
144 }
145 message The location in which to store the returned message. If a
147 suitable message return buffer is supplied, this function is
148 thread safe.
149 message_size
151 The size in bytes of the location in which to store the
152 returned message.
153 errnum The error value to be decoded, usually obtained from the errno
155 global variable just before this function is called. This is
156 necessary if you need to call any code between the system call
157 to be explained and this function, because many libc functions
158 will alter the value of errno.
159 c The original c, exactly as passed to the fputc(3) system call.
161 fp The original fp, exactly as passed to the fputc(3) system call.
163
165 fputc(3)
166 output of characters
167 explain_fputc_or_die(3)
169 output of characters and report errors
170
172 libexplain version 1.4
173 Copyright (C) 2008 Peter Miller
174 explain_fputc(3)