NAME

fmtmsg - display a message on stderr or 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

Based on a message's classification component, fmtmsg writes a formatted message to stderr, to the console, or to both.

fmtmsg can be used instead of the traditional printf interface to display messages to stderr. fmtmsg, in conjunction with gettxt, provides a simple interface for producing language-independent applications.

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

classification

Contains identifiers from the following groups of major classifications and subclassifications. Any one identifier from a subclass may be used in combination by ORing the values together 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 stderr and the system console).

``Major classifications'' identify the source of the condition. Identifiers are: MM_HARD (hardware), MM_SOFT (software), and MM_FIRM (firmware).

``Message source subclassifications'' identify the type of software in which the problem is spotted. Identifiers are: MM_APPL (application), MM_UTIL (utility), and MM_OPSYS (operating system).

``Display subclassifications'' indicate 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. Neither, either, or both identifiers may be used.

``Status subclassifications'' indicate whether the application will 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  of
      this  component  is  two  fields separated by a colon.
      The first field is  up  to  10  characters  long;  the
      second  is  up  to  14 characters.  Suggested usage is
      that label identifies the package in which the  appli-
      cation  resides  as well as the program or application
      name.  For example, the  label  UX:cat  indicates  the
      UNIX System V package and the cat application.

severity

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

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

MM_ERROR indicates that the application has detected a fault. Produces the print string ERROR.

MM_WARNING indicates a condition out of the ordinary that might be a problem and should be watched. Produces the print string WARNING.

MM_INFO provides information about a condition that is not in error. Produces the print string INFO.

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

Other severity levels may be added by using the addseverity routine.

text Describes the condition that produced the message. The text string is not limited to a specific size.

action

Describes the first step to be taken in the error recovery process. fmtmsg precedes each action string with the prefix: TO FIX:. The action string is not limited to a specific size.

tag An identifier which references on-line documentation for the message. Suggested usage is that tag includes the label and a unique identifying number. A sample tag is UX:cat:146.

Environment Variables

There  are  two  environment  variables  that  control   the
behavior  of  fmtmsg:  MSGVERB and SEV_LEVEL.  MSGVERB tells
fmtmsg which message components it is to select when writing
messages  to  stderr.   The  value  of  MSGVERB  is a colon-
separated list of optional keywords.  MSGVERB can be set  as
follows:
     MSGVERB=[keyword[:keyword[:...]]]
     export MSGVERB
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
includes that component in the message when writing the mes-
sage to stderr.  If MSGVERB does not include a keyword for a
message  component,  that  component  is not 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 selects all components.

The first time fmtmsg is called, it examines the MSGVERB environment variable to see which message components it is to select when generating a message to write to the standard error stream, stderr. The values accepted on the initial call are saved for future calls.

MSGVERB affects only which components are selected for display to the standard error stream. All message components are included in console messages.

SEV_LEVEL defines severity levels and associates print strings with them for use by fmtmsg. The standard severity levels shown below cannot be modified. Additional severity levels can also be defined, redefined, and removed using addseverity [see addseverity(3C)]. If the same severity level is defined by both SEV_LEVEL and addseverity, the definition by addseverity is controlling.

0   (no severity is used)
1   HALT
2   ERROR
3   WARNING
4   INFO

SEV_LEVEL can be set as follows:

     SEV_LEVEL=[description[:description[:...]]]
     export SEV_LEVEL
description  is  a  comma-separated  list  containing  three
fields:
     description=severity_keyword,level,printstring
severity_keyword is a character string that is used  as  the
keyword  on  the  -s  severity option to the fmtmsg command.
(This field is not used by the fmtmsg function.)  level is a
character string that evaluates to a positive integer (other
than 0, 1, 2, 3, or 4, which are reserved for  the  standard
severity  levels).  If the keyword severity_keyword is used,
level is the severity value passed on to  the  fmtmsg  func-
tion.  printstring is the character string used by fmtmsg in
the standard message  format  whenever  the  severity  value
level is used.

If a description in the colon list is not a three-field comma list, or, if the second field of a comma list does not evaluate to a positive integer, that description in the colon list is ignored.

The first time fmtmsg is called, it examines the SEV_LEVEL environment variable, if defined, to see whether the environment expands the levels of severity beyond the five standard levels and those defined using addseverity. The values accepted on the initial call are saved for future calls.

Use in Applications

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.

The table below indicates the null values and identifiers for fmtmsg arguments.

 ______________________________________________
|_Argument___Type_____Null-Value____Identifier|
| label      char*   (char*) NULL   MM_NULLLBL|
| severity   int     0              MM_NULLSEV|
| class      long    0L             MM_NULLMC |
| text       char*   (char*) NULL   MM_NULLTXT|
| action     char*   (char*) NULL   MM_NULLACT|
| tag        char*   (char*) NULL   MM_NULLTAG|
|_____________________________________________|

Another means of systematically omitting a component is by omitting the component keyword(s) when defining the MSGVERB environment variable (see the ``Environment Variables'' section).

EXAMPLES

Example 1:

The following example of fmtmsg:

fmtmsg(MM_PRINT, "UX:cat", MM_ERROR, "invalid  syntax",
"refer to manual", "UX:cat:001")

produces a complete message in the standard message format:

     UX:cat: ERROR: invalid syntax

              TO FIX: refer to manual   UX:cat:001

Example 2:

When the environment variable MSGVERB is set as follows:

MSGVERB=severity:text:action

and the Example 1 is used, fmtmsg produces:

     ERROR: invalid syntax
     TO FIX: refer to manual

Example 3:

When the environment variable SEV_LEVEL is set as follows:

SEV_LEVEL=note,5,NOTE

the following call to fmtmsg:

fmtmsg(MM_UTIL | MM_PRINT, "UX:cat", 5,  "invalid  syn-
tax", "refer to manual", "UX:cat:001")

produces:

UX:cat: NOTE: invalid syntax

         TO FIX: refer to manual   UX:cat:001

SEE ALSO

addseverity(3C), gettxt(3C), printf(3S).
fmtmsg(1) in the User's Reference Manual.

DIAGNOSTICS

The exit codes for fmtmsg are the following:

MM_OK The function succeeded.

MM_NOTOK The function failed completely.

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

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