fmtmsg(3p) — Linux manual page


FMTMSG(3P)                POSIX Programmer's Manual               FMTMSG(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       fmtmsg — display a message in the specified format on standard error
       and/or a system console

SYNOPSIS         top

       #include <fmtmsg.h>

       int fmtmsg(long classification, const char *label, int severity,
           const char *text, const char *action, const char *tag);

DESCRIPTION         top

       The fmtmsg() function shall display messages in a specified format
       instead of the traditional printf() function.

       Based on a message's classification component, fmtmsg() shall write a
       formatted message either to standard error, to the console, or to

       A formatted message consists of up to five components as defined
       below. The component classification is not part of a message
       displayed to the user, but defines the source of the message and
       directs the display of the formatted message.

                   Contains the sum of identifying values constructed from
                   the constants defined below. Any one identifier from a
                   subclass may be used in combination with a single
                   identifier from a different subclass. Two or more
                   identifiers from the same subclass should not be used
                   together, with the exception of identifiers from the
                   display subclass. (Both display subclass identifiers may
                   be used so that messages can be displayed to both
                   standard error and the system console.)

                   Major Classifications
                         Identifies the source of the condition. Identifiers
                         are: MM_HARD (hardware), MM_SOFT (software), and
                         MM_FIRM (firmware).

                   Message Source Subclassifications
                         Identifies the type of software in which the
                         problem is detected.  Identifiers are: MM_APPL
                         (application), MM_UTIL (utility), and MM_OPSYS
                         (operating system).

                   Display Subclassifications
                         Indicates where the message is to be displayed.
                         Identifiers are: MM_PRINT to display the message on
                         the standard error stream, MM_CONSOLE to display
                         the message on the system console. One or both
                         identifiers may be used.

                   Status Subclassifications
                         Indicates whether the application can recover from
                         the condition.  Identifiers are: MM_RECOVER
                         (recoverable) and MM_NRECOV (non-recoverable).

                   An additional identifier, MM_NULLMC, indicates that no
                   classification component is supplied for the message.

       label       Identifies the source of the message. The format is two
                   fields separated by a <colon>.  The first field is up to
                   10 bytes, the second is up to 14 bytes.

       severity    Indicates the seriousness of the condition. Identifiers
                   for the levels of severity are:

                   MM_HALT     Indicates that the application has
                               encountered a severe fault and is halting.
                               Produces the string "HALT".

                   MM_ERROR    Indicates that the application has detected a
                               fault. Produces the string "ERROR".

                   MM_WARNING  Indicates a condition that is out of the
                               ordinary, that might be a problem, and should
                               be watched. Produces the string "WARNING".

                   MM_INFO     Provides information about a condition that
                               is not in error. Produces the string "INFO".

                   MM_NOSEV    Indicates that no severity level is supplied
                               for the message.

       text        Describes the error condition that produced the message.
                   The character string is not limited to a specific size.
                   If the character string is empty, then the text produced
                   is unspecified.

       action      Describes the first step to be taken in the error-
                   recovery process.  The fmtmsg() function precedes the
                   action string with the prefix: "TOFIX:".  The action
                   string is not limited to a specific size.

       tag         An identifier that references on-line documentation for
                   the message.  Suggested usage is that tag includes the
                   label and a unique identifying number. A sample tag is

       The MSGVERB environment variable (for message verbosity) shall
       determine for fmtmsg() which message components it is to select when
       writing messages to standard error. The value of MSGVERB shall be a
       <colon>-separated list of optional keywords. Valid keywords are:
       label, severity, text, action, and tag. If MSGVERB contains a keyword
       for a component and the component's value is not the component's null
       value, fmtmsg() shall include that component in the message when
       writing the message to standard error. If MSGVERB does not include a
       keyword for a message component, that component shall not be included
       in the display of the message. The keywords may appear in any order.
       If MSGVERB is not defined, if its value is the null string, if its
       value is not of the correct format, or if it contains keywords other
       than the valid ones listed above, fmtmsg() shall select all

       MSGVERB shall determine which components are selected for display to
       standard error. All message components shall be included in console

RETURN VALUE         top

       The fmtmsg() function shall return one of the following values:

       MM_OK       The function succeeded.

       MM_NOTOK    The function failed completely.

       MM_NOMSG    The function was unable to generate a message on standard
                   error, but otherwise succeeded.

       MM_NOCON    The function was unable to generate a console message,
                   but otherwise succeeded.

ERRORS         top


       The following sections are informative.

EXAMPLES         top

        1. The following example of fmtmsg():

               fmtmsg(MM_PRINT, "XSI:cat", MM_ERROR, "illegal option",
               "refer to cat in user's reference manual", "XSI:cat:001")

           produces a complete message in the specified message format:

               XSI:cat: ERROR: illegal option
               TO FIX: refer to cat in user's reference manual XSI:cat:001

        2. When the environment variable MSGVERB is set as follows:


           and Example 1 is used, fmtmsg() produces:

               ERROR: illegal option
               TO FIX: refer to cat in user's reference manual


       One or more message components may be systematically omitted from
       messages generated by an application by using the null value of the
       argument for that component.

RATIONALE         top




SEE ALSO         top


       The Base Definitions volume of POSIX.1‐2008, fmtmsg.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see .

IEEE/The Open Group                 2013                          FMTMSG(3P)

Pages that refer to this page: fmtmsg.h(0p)