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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 (consult 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 con-
              stants  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 condi-
              tion.  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 char-
              acter 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 mes-
              sage.  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 deter-
       mine for fmtmsg() which message components it is to select when writing
       messages to standard error. The value of MSGVERB shall be a colon-sepa-
       rated 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 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  oth-
              erwise 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 mes-
       sages generated by an application by using the null value of the  argu-
       ment 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,  Copyright  (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.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                           FMTMSG(3P)