1FMTMSG(3P) POSIX Programmer's Manual FMTMSG(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 fmtmsg — display a message in the specified format on standard error
14 and/or a system console
15
17 #include <fmtmsg.h>
18 int fmtmsg(long classification, const char *label, int severity,
20 const char *text, const char *action, const char *tag);
21
23 The fmtmsg() function shall display messages in a specified format
24 instead of the traditional printf() function.
25 Based on a message's classification component, fmtmsg() shall write a
27 formatted message either to standard error, to the console, or to both.
28 A formatted message consists of up to five components as defined below.
30 The component classification is not part of a message displayed to the
31 user, but defines the source of the message and directs the display of
32 the formatted message.
33 classification
35 Contains the sum of identifying values constructed from the
36 constants defined below. Any one identifier from a subclass
37 may be used in combination with a single identifier from a
38 different subclass. Two or more identifiers from the same
39 subclass should not be used together, with the exception of
40 identifiers from the display subclass. (Both display sub‐
41 class identifiers may be used so that messages can be dis‐
42 played to both standard error and the system console.)
43 Major Classifications
45 Identifies the source of the condition. Identifiers
46 are: MM_HARD (hardware), MM_SOFT (software), and
47 MM_FIRM (firmware).
48 Message Source Subclassifications
50 Identifies the type of software in which the problem
51 is detected. Identifiers are: MM_APPL (application),
52 MM_UTIL (utility), and MM_OPSYS (operating system).
53 Display Subclassifications
55 Indicates where the message is to be displayed. Iden‐
56 tifiers are: MM_PRINT to display the message on the
57 standard error stream, MM_CONSOLE to display the mes‐
58 sage on the system console. One or both identifiers
59 may be used.
60 Status Subclassifications
62 Indicates whether the application can recover from
63 the condition. Identifiers are: MM_RECOVER (recover‐
64 able) and MM_NRECOV (non-recoverable).
65 An additional identifier, MM_NULLMC, indicates that no
67 classification component is supplied for the message.
68 label Identifies the source of the message. The format is two
70 fields separated by a <colon>. The first field is up to 10
71 bytes, the second is up to 14 bytes.
72 severity Indicates the seriousness of the condition. Identifiers for
74 the levels of severity are:
75 MM_HALT Indicates that the application has encountered
77 a severe fault and is halting. Produces the
78 string "HALT".
79 MM_ERROR Indicates that the application has detected a
81 fault. Produces the string "ERROR".
82 MM_WARNING Indicates a condition that is out of the ordi‐
84 nary, that might be a problem, and should be
85 watched. Produces the string "WARNING".
86 MM_INFO Provides information about a condition that is
88 not in error. Produces the string "INFO".
89 MM_NOSEV Indicates that no severity level is supplied
91 for the message.
92 text Describes the error condition that produced the message.
94 The character string is not limited to a specific size. If
95 the character string is empty, then the text produced is
96 unspecified.
97 action Describes the first step to be taken in the error-recovery
99 process. The fmtmsg() function precedes the action string
100 with the prefix: "TOFIX:". The action string is not lim‐
101 ited to a specific size.
102 tag An identifier that references on-line documentation for the
104 message. Suggested usage is that tag includes the label
105 and a unique identifying number. A sample tag is
106 "XSI:cat:146".
107 The MSGVERB environment variable (for message verbosity) shall deter‐
109 mine for fmtmsg() which message components it is to select when writing
110 messages to standard error. The value of MSGVERB shall be a
111 <colon>-separated list of optional keywords. Valid keywords are: label,
112 severity, text, action, and tag. If MSGVERB contains a keyword for a
113 component and the component's value is not the component's null value,
114 fmtmsg() shall include that component in the message when writing the
115 message to standard error. If MSGVERB does not include a keyword for a
116 message component, that component shall not be included in the display
117 of the message. The keywords may appear in any order. If MSGVERB is not
118 defined, if its value is the null string, if its value is not of the
119 correct format, or if it contains keywords other than the valid ones
120 listed above, fmtmsg() shall select all components.
121 MSGVERB shall determine which components are selected for display to
123 standard error. All message components shall be included in console
124 messages.
125
127 The fmtmsg() function shall return one of the following values:
128 MM_OK The function succeeded.
130 MM_NOTOK The function failed completely.
132 MM_NOMSG The function was unable to generate a message on standard
134 error, but otherwise succeeded.
135 MM_NOCON The function was unable to generate a console message, but
137 otherwise succeeded.
138
140 None.
141 The following sections are informative.
143
145 1. The following example of fmtmsg():
146 fmtmsg(MM_PRINT, "XSI:cat", MM_ERROR, "illegal option",
148 "refer to cat in user's reference manual", "XSI:cat:001")
149 produces a complete message in the specified message format:
151 XSI:cat: ERROR: illegal option
153 TO FIX: refer to cat in user's reference manual XSI:cat:001
154 2. When the environment variable MSGVERB is set as follows:
156 MSGVERB=severity:text:action
158 and Example 1 is used, fmtmsg() produces:
160 ERROR: illegal option
162 TO FIX: refer to cat in user's reference manual
163
165 One or more message components may be systematically omitted from mes‐
166 sages generated by an application by using the null value of the argu‐
167 ment for that component.
168
170 None.
171
173 None.
174
176 fprintf()
177 The Base Definitions volume of POSIX.1‐2008, <fmtmsg.h>
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181 Portions of this text are reprinted and reproduced in electronic form
182 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
183 -- Portable Operating System Interface (POSIX), The Open Group Base
184 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
185 cal and Electronics Engineers, Inc and The Open Group. (This is
186 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
187 event of any discrepancy between this version and the original IEEE and
188 The Open Group Standard, the original IEEE and The Open Group Standard
189 is the referee document. The original Standard can be obtained online
190 at http://www.unix.org/online.html .
191 Any typographical or formatting errors that appear in this page are
193 most likely to have been introduced during the conversion of the source
194 files to man page format. To report such errors, see https://www.ker‐
195 nel.org/doc/man-pages/reporting_bugs.html .
196IEEE/The Open Group 2013 FMTMSG(3P)