FMTMSG(3)

NAME
fmtmsg - format and display a message

LIBRARY
libc

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 can be used to display messages in the specified format. Messages may be written either to standard error, to the console, or both.

A formatted message consists of up to five components specified in label, severity, text, action and tag. Further information such as the origin of the message, the recoverability from the condition causing the message and where to display the message is specified in classification.

  Classification
The classification argument consists of a major classification and several sub-classifications. It has no effect on the content of the message displayed. With the exception of the display sub-classification, only a single identifier may be specified for each (sub-)classification. The following classifications are available:

Major classifications
    The source of the condition. Available identifiers are: MM_HARD (hardware), MM_SOFT (software), and MM_FIRM (firmware).

Message source sub-classifications
    The type of software detecting the condition. Available identifiers are: MM_APPL (application), MM_UTIL (utility), and MM_OPSYS (operating system).

Display sub-classifications
    The displays the formatted messages is to be written to. Available identifiers are: MM_PRINT (standard error stream) and MM_CONSOLE (system console).

Status sub-classifications
    The capability of the calling software to recover from the condition. Available identifiers are: MM_RECOVER (recoverable) and MM_NRECOV (non-recoverable).

If no classification is to be supplied, MM_NULLMC must be specified.

  Label
The label argument identifies the source of the message. It consists of two fields separated by a colon (:). The first field is up to 10 characters, the second is up to 14 characters.

If no label is to be supplied, MM_NULLLBL must be specified.

  Severity
The seriousness of the condition causing the message. The following severity levels are available:

MM_HALT
    The software has encountered a severe fault and is halting.

MM_ERROR
    The software has encountered a fault.

MM_WARNING
    The software has encountered an unusual non-fault condition.

MM_INFO
    The software informs about a non-error condition.

If no severity level is to be supplied, MM_NOSEV must be specified.

  Text
The description of the condition the software encountered. The character string is not limited to a specific size.

If no text is to be supplied, MM_NOTXT must be specified.

  Action
The first step to be taken to recover from the condition the software encountered; it will be preceded by the prefix “TO FIX:”. The character string is not limited to a specific size.

If no action is to be supplied, MM_NOACT must be specified.

  Tag
The on-line documentation which provides further information about the condition and the message, such as “fmtmsg(3)”. The character string is not limited to a specific size.

If no tag is to be supplied, MM_NOTAG must be specified.

Further effect on the formatting of the message as displayed on the standard error stream (but not on the system console!) may be taken by setting the MSGVERB environment variable, which selects the subset of message components to be printed. It consists of a colon-separated list of the optional keywords label, severity, text, action, and tag, which correspond to the arguments to fmtmsg() with the same names. If MSGVERB is either not set or malformed (containing empty or unknown keywords), its content is ignored an all message components will be selected.

Note that displaying a message on the system console may fail due to inappropriate privileges or a non-permissive file mode of the console device.

RETURN VALUES
The fmtmsg() function returns 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_NOCOM
    The function was unable to generate a message on the console, but otherwise succeeded.

SEE ALSO
printf(3), syslog(3)

STANDARDS
The fmtmsg() function conforms to xsh5.