1explain_strtod(3) Library Functions Manual explain_strtod(3)
2
6 explain_strtod - explain strtod(3) errors
7
9 #include <libexplain/strtod.h>
10 const char *explain_strtod(const char *nptr, char **endptr);
11 const char *explain_errno_strtod(int errnum, const char *nptr, char
12 **endptr);
13 void explain_message_strtod(char *message, int message_size, const char
14 *nptr, char **endptr);
15 void explain_message_errno_strtod(char *message, int message_size, int
16 errnum, const char *nptr, char **endptr);
17
19 These functions may be used to obtain explanations for errors returned
20 by the strtod(3) system call.
21 explain_strtod
23 const char *explain_strtod(const char *nptr, char **endptr);
24 The explain_strtod function is used to obtain an explanation of an
26 error returned by the strtod(3) system call. The least the message will
27 contain is the value of strerror(errno), but usually it will do much
28 better, and indicate the underlying cause in more detail.
29 The errno global variable will be used to obtain the error value to be
31 decoded.
32 nptr The original nptr, exactly as passed to the strtod(3) system
34 call.
35 endptr The original endptr, exactly as passed to the strtod(3) system
37 call.
38 Returns:
40 The message explaining the error. This message buffer is shared
41 by all libexplain functions which do not supply a buffer in
42 their argument list. This will be overwritten by the next call
43 to any libexplain function which shares this buffer, including
44 other threads.
45 Note: This function is not thread safe, because it shares a return buf‐
47 fer across all threads, and many other functions in this library.
48 Example: This function is intended to be used in a fashion similar to
50 the following example:
51 double result = strtod(nptr, endptr);
52 if (result < 0)
53 {
54 fprintf(stderr, "%s\n", explain_strtod(nptr, endptr));
55 exit(EXIT_FAILURE);
56 }
57 The above code example is available pre‐packaged as the explain_str‐
59 tod_or_die(3) function.
60 explain_errno_strtod
62 const char *explain_errno_strtod(int errnum, const char *nptr, char
63 **endptr);
64 The explain_errno_strtod function is used to obtain an explanation of
66 an error returned by the strtod(3) system call. The least the message
67 will contain is the value of strerror(errno), but usually it will do
68 much better, and indicate the underlying cause in more detail.
69 errnum The error value to be decoded, usually obtained from the errno
71 global variable just before this function is called. This is
72 necessary if you need to call any code between the system call
73 to be explained and this function, because many libc functions
74 will alter the value of errno.
75 nptr The original nptr, exactly as passed to the strtod(3) system
77 call.
78 endptr The original endptr, exactly as passed to the strtod(3) system
80 call.
81 Returns:
83 The message explaining the error. This message buffer is shared
84 by all libexplain functions which do not supply a buffer in
85 their argument list. This will be overwritten by the next call
86 to any libexplain function which shares this buffer, including
87 other threads.
88 Note: This function is not thread safe, because it shares a return buf‐
90 fer across all threads, and many other functions in this library.
91 Example: This function is intended to be used in a fashion similar to
93 the following example:
94 double result = strtod(nptr, endptr);
95 if (result < 0)
96 {
97 int err = errno;
98 fprintf(stderr, "%s\n", explain_errno_strtod(err, nptr,
99 endptr));
100 exit(EXIT_FAILURE);
101 }
102 The above code example is available pre‐packaged as the explain_str‐
104 tod_or_die(3) function.
105 explain_message_strtod
107 void explain_message_strtod(char *message, int message_size, const char
108 *nptr, char **endptr);
109 The explain_message_strtod function is used to obtain an explanation of
111 an error returned by the strtod(3) system call. The least the message
112 will contain is the value of strerror(errno), but usually it will do
113 much better, and indicate the underlying cause in more detail.
114 The errno global variable will be used to obtain the error value to be
116 decoded.
117 message The location in which to store the returned message. If a suit‐
119 able message return buffer is supplied, this function is thread
120 safe.
121 message_size
123 The size in bytes of the location in which to store the
124 returned message.
125 nptr The original nptr, exactly as passed to the strtod(3) system
127 call.
128 endptr The original endptr, exactly as passed to the strtod(3) system
130 call.
131 Example: This function is intended to be used in a fashion similar to
133 the following example:
134 double result = strtod(nptr, endptr);
135 if (result < 0)
136 {
137 char message[3000];
138 explain_message_strtod(message, sizeof(message), nptr,
139 endptr);
140 fprintf(stderr, "%s\n", message);
141 exit(EXIT_FAILURE);
142 }
143 The above code example is available pre‐packaged as the explain_str‐
145 tod_or_die(3) function.
146 explain_message_errno_strtod
148 void explain_message_errno_strtod(char *message, int message_size, int
149 errnum, const char *nptr, char **endptr);
150 The explain_message_errno_strtod function is used to obtain an explana‐
152 tion of an error returned by the strtod(3) system call. The least the
153 message will contain is the value of strerror(errno), but usually it
154 will do much better, and indicate the underlying cause in more detail.
155 message The location in which to store the returned message. If a suit‐
157 able message return buffer is supplied, this function is thread
158 safe.
159 message_size
161 The size in bytes of the location in which to store the
162 returned message.
163 errnum The error value to be decoded, usually obtained from the errno
165 global variable just before this function is called. This is
166 necessary if you need to call any code between the system call
167 to be explained and this function, because many libc functions
168 will alter the value of errno.
169 nptr The original nptr, exactly as passed to the strtod(3) system
171 call.
172 endptr The original endptr, exactly as passed to the strtod(3) system
174 call.
175 Example: This function is intended to be used in a fashion similar to
177 the following example:
178 double result = strtod(nptr, endptr);
179 if (result < 0)
180 {
181 int err = errno;
182 char message[3000];
183 explain_message_errno_strtod(message, sizeof(message), err,
184 nptr, endptr);
185 fprintf(stderr, "%s\n", message);
186 exit(EXIT_FAILURE);
187 }
188 The above code example is available pre‐packaged as the explain_str‐
190 tod_or_die(3) function.
191
193 strtod(3)
194 convert ASCII string to floating‐point number
195 explain_strtod_or_die(3)
197 convert ASCII string to floating‐point number and report errors
198
200 libexplain version 1.4
201 Copyright (C) 2009 Peter Miller
202 explain_strtod(3)