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