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
12 fmtmsg - display a message in the specified format on standard error
13 and/or a system console
14
16 #include <fmtmsg.h>
17 int fmtmsg(long classification, const char *label, int severity,
19 const char *text, const char *action, const char *tag);
20
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 con‐
36 stants defined below. Any one identifier from a subclass may be
37 used in combination with a single identifier from a different
38 subclass. Two or more identifiers from the same subclass should
39 not be used together, with the exception of identifiers from the
40 display subclass. (Both display subclass identifiers may be used
41 so that messages can be displayed to both standard error and the
42 system console.)
43 Major Classifications
45 Identifies the source of the condition. Identifiers are: MM_HARD
47 (hardware), MM_SOFT (software), and MM_FIRM (firmware).
48 Message Source Subclassifications
50 Identifies the type of software in which the problem is
52 detected. Identifiers are: MM_APPL (application), MM_UTIL
53 (utility), and MM_OPSYS (operating system).
54 Display Subclassifications
56 Indicates where the message is to be displayed. Identifiers are:
58 MM_PRINT to display the message on the standard error stream,
59 MM_CONSOLE to display the message on the system console. One or
60 both identifiers may be used.
61 Status Subclassifications
63 Indicates whether the application can recover from the condi‐
65 tion. Identifiers are: MM_RECOVER (recoverable) and MM_NRECOV
66 (non-recoverable).
67 An additional identifier, MM_NULLMC, indicates that no classification
70 component is supplied for the message.
71 label Identifies the source of the message. The format is two fields
73 separated by a colon. The first field is up to 10 bytes, the
74 second is up to 14 bytes.
75 severity
77 Indicates the seriousness of the condition. Identifiers for the
78 levels of severity are:
79 MM_HALT
81 Indicates that the application has encountered a severe fault
82 and is halting. Produces the string "HALT" .
83 MM_ERROR
85 Indicates that the application has detected a fault. Produces
86 the string "ERROR" .
87 MM_WARNING
89 Indicates a condition that is out of the ordinary, that might be
90 a problem, and should be watched. Produces the string "WARNING"
91 .
92 MM_INFO
94 Provides information about a condition that is not in error.
95 Produces the string "INFO" .
96 MM_NOSEV
98 Indicates that no severity level is supplied for the message.
99 text Describes the error condition that produced the message. The
102 character string is not limited to a specific size. If the char‐
103 acter string is empty, then the text produced is unspecified.
104 action Describes the first step to be taken in the error-recovery
106 process. The fmtmsg() function precedes the action string with
107 the prefix: "TO FIX:" . The action string is not limited to a
108 specific size.
109 tag An identifier that references on-line documentation for the mes‐
111 sage. Suggested usage is that tag includes the label and a
112 unique identifying number. A sample tag is "XSI:cat:146" .
113 The MSGVERB environment variable (for message verbosity) shall deter‐
116 mine for fmtmsg() which message components it is to select when writing
117 messages to standard error. The value of MSGVERB shall be a colon-sepa‐
118 rated list of optional keywords. Valid keywords are: label, severity,
119 text, action, and tag. If MSGVERB contains a keyword for a component
120 and the component's value is not the component's null value, fmtmsg()
121 shall include that component in the message when writing the message to
122 standard error. If MSGVERB does not include a keyword for a message
123 component, that component shall not be included in the display of the
124 message. The keywords may appear in any order. If MSGVERB is not
125 defined, if its value is the null string, if its value is not of the
126 correct format, or if it contains keywords other than the valid ones
127 listed above, fmtmsg() shall select all components.
128 MSGVERB shall determine which components are selected for display to
130 standard error. All message components shall be included in console
131 messages.
132
134 The fmtmsg() function shall return one of the following values:
135 MM_OK The function succeeded.
137 MM_NOTOK
139 The function failed completely.
140 MM_NOMSG
142 The function was unable to generate a message on standard error,
143 but otherwise succeeded.
144 MM_NOCON
146 The function was unable to generate a console message, but oth‐
147 erwise succeeded.
148
151 None.
152 The following sections are informative.
154
156 1. The following example of fmtmsg():
157 fmtmsg(MM_PRINT, "XSI:cat", MM_ERROR, "illegal option",
160 "refer to cat in user's reference manual", "XSI:cat:001")
161 produces a complete message in the specified message format:
163 XSI:cat: ERROR: illegal option
166 TO FIX: refer to cat in user's reference manual XSI:cat:001
167 2. When the environment variable MSGVERB is set as follows:
169 MSGVERB=severity:text:action
172 and Example 1 is used, fmtmsg() produces:
174 ERROR: illegal option
177 TO FIX: refer to cat in user's reference manual
178
180 One or more message components may be systematically omitted from mes‐
181 sages generated by an application by using the null value of the argu‐
182 ment for that component.
183
185 None.
186
188 None.
189
191 printf(), the Base Definitions volume of IEEE Std 1003.1-2001,
192 <fmtmsg.h>
193
195 Portions of this text are reprinted and reproduced in electronic form
196 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
197 -- Portable Operating System Interface (POSIX), The Open Group Base
198 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
199 Electrical and Electronics Engineers, Inc and The Open Group. In the
200 event of any discrepancy between this version and the original IEEE and
201 The Open Group Standard, the original IEEE and The Open Group Standard
202 is the referee document. The original Standard can be obtained online
203 at http://www.opengroup.org/unix/online.html .
204IEEE/The Open Group 2003 FMTMSG(3P)