1explain_getchar(3) Library Functions Manual explain_getchar(3)
2
6 explain_getchar - explain getchar(3) errors
7
9 #include <libexplain/getchar.h>
10 const char *explain_getchar(void);
11 const char *explain_errno_getchar(int errnum, void);
12 void explain_message_getchar(char *message, int message_size);
13 void explain_message_errno_getchar(char *message, int message_size, int
14 errnum);
15
17 These functions may be used to obtain explanations for errors returned
18 by the getchar(3) system call.
19 explain_getchar
21 const char *explain_getchar(void);
22 The explain_getchar function is used to obtain an explanation of an
24 error returned by the getchar(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 int c = getchar();
34 if (c == EOF && ferror(stdin))
35 {
36 fprintf(stderr, "%s\n", explain_getchar());
37 exit(EXIT_FAILURE);
38 }
39 Returns:
41 The message explaining the error. This message buffer is
42 shared by all libexplain functions which do not supply a buffer
43 in their argument list. This will be overwritten by the next
44 call to any libexplain function which shares this buffer,
45 including other threads.
46 Note: This function is not thread safe, because it shares a return buf‐
48 fer across all threads, and many other functions in this library.
49 explain_errno_getchar
51 const char *explain_errno_getchar(int errnum);
52 The explain_errno_getchar function is used to obtain an explanation of
54 an error returned by the getchar(3) system call. The least the message
55 will contain is the value of strerror(errnum), but usually it will do
56 much better, and indicate the underlying cause in more detail.
57 This function is intended to be used in a fashion similar to the fol‐
59 lowing example:
60 int c = getchar();
61 if (c == EOF && ferror(stdin))
62 {
63 int err = errno;
64 fprintf(stderr, "%s\n", explain_errno_getchar(err, ));
65 exit(EXIT_FAILURE);
66 }
67 errnum The error value to be decoded, usually obtained from the errno
69 global variable just before this function is called. This is
70 necessary if you need to call any code between the system call
71 to be explained and this function, because many libc functions
72 will alter the value of errno.
73 Returns:
75 The message explaining the error. This message buffer is
76 shared by all libexplain functions which do not supply a buffer
77 in their argument list. This will be overwritten by the next
78 call to any libexplain function which shares this buffer,
79 including other threads.
80 Note: This function is not thread safe, because it shares a return buf‐
82 fer across all threads, and many other functions in this library.
83 explain_message_getchar
85 void explain_message_getchar(char *message, int message_size);
86 The explain_message_getchar function may be used to obtain an explana‐
88 tion of an error returned by the getchar(3) system call. The least the
89 message will contain is the value of strerror(errno), but usually it
90 will do much better, and indicate the underlying cause in more detail.
91 The errno global variable will be used to obtain the error value to be
93 decoded.
94 This function is intended to be used in a fashion similar to the fol‐
96 lowing example:
97 int c = getchar();
98 if (c == EOF && ferror(stdin))
99 {
100 char message[3000];
101 explain_message_getchar(message, sizeof(message), );
102 fprintf(stderr, "%s\n", message);
103 exit(EXIT_FAILURE);
104 }
105 message The location in which to store the returned message. If a
107 suitable message return buffer is supplied, this function is
108 thread safe.
109 message_size
111 The size in bytes of the location in which to store the
112 returned message.
113 explain_message_errno_getchar
115 void explain_message_errno_getchar(char *message, int message_size, int
116 errnum);
117 The explain_message_errno_getchar function may be used to obtain an
119 explanation of an error returned by the getchar(3) system call. The
120 least the message will contain is the value of strerror(errnum), but
121 usually it will do much better, and indicate the underlying cause in
122 more detail.
123 This function is intended to be used in a fashion similar to the fol‐
125 lowing example:
126 int c = getchar();
127 if (c == EOF && ferror(stdin))
128 {
129 int err = errno;
130 char message[3000];
131 explain_message_errno_getchar(message, sizeof(message), err, );
132 fprintf(stderr, "%s\n", message);
133 exit(EXIT_FAILURE);
134 }
135 message The location in which to store the returned message. If a
137 suitable message return buffer is supplied, this function is
138 thread safe.
139 message_size
141 The size in bytes of the location in which to store the
142 returned message.
143 errnum The error value to be decoded, usually obtained from the errno
145 global variable just before this function is called. This is
146 necessary if you need to call any code between the system call
147 to be explained and this function, because many libc functions
148 will alter the value of errno.
149
151 getchar(3)
152 input of characters
153 explain_getchar_or_die(3)
155 input of characters and report errors
156
158 libexplain version 1.4
159 Copyright (C) 2008 Peter Miller
160 explain_getchar(3)