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



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

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

SYNOPSIS
       #include <fmtmsg.h>

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


DESCRIPTION
       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 both.

       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.

       classification
              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: "TO FIX:" . 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 "XSI:cat:146" .


       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 key-
       words. 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 components.

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

RETURN VALUE
       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
       None.

       The following sections are informative.

EXAMPLES
        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:


           MSGVERB=severity:text:action

       and Example 1 is used, fmtmsg() produces:


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

APPLICATION USAGE
       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
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       printf(), the Base Definitions volume of IEEE Std 1003.1-2001, <fmtmsg.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    FMTMSG(3P)