LOG4SAS_APPENDER Function

Creates a fileref appender that can be referenced by a logger.

Category:	Logging
Example:	Logging Example Using Functions

Table of Contents

Syntax

LOG4SAS_APPENDER("name", "FileRefAppender", 'options')

Required Arguments

"name"

specifies a name for the appender.

Tip	The appender name is case sensitive.

"FileRefAppender": specifies that a fileref is used as the destination for the appender.

'options'

specify one or more of the following values:

FILEREF=fileref

specifies a fileref that is used as the log message destination for this appender.

Requirement

Yes

PATTERN="pattern"

specifies one or more message layout patterns that are used to format the log message.

See	Pattern Layouts

THRESHOLD="threshold": specifies a level at which log events that are lower than threshold are filtered out for the appender. Valid values for threshold, from lowest to highest, are TRACE, DEBUG, INFO, WARN, ERROR, and FATAL.

Requirement

Options must be enclosed in single quotation marks.

Details

Appender Names

Appender names follow SAS naming conventions. An appender is associated with a logger by using the appender name as one of the values of the APPENDER-REF option in the LOG4SAS_LOGGER function.

FileRefAppender

A FileRefAppender is the only type of appender that can be used in the SAS language.

Patterns

Patterns are a feature of SAS logging that enable you to associate a layout with a particular logging output destination. The layout specifies how the output is formatted before it is sent to the output destination. The layout is specified as a pattern string that is similar to the pattern strings that are used in the C language PRINTF statement. The pattern layout contains literal text and format directives that are called conversion specifiers.

Each conversion specifier has the following syntax:

%[format_modifiers]conversion_character

If a pattern is not specified, the default is the message.

For more information, see Pattern Layouts.

Thresholds

An appender can be defined to have a threshold level. By default, appenders do not have a threshold. When a threshold is set, all log events that have a level that is lower than the threshold level are ignored by the appender.

For more information, see Logging Thresholds.

Processing Appenders in the DATA Step

An appender needs to be created only one time for each DATA step. Because the DATA step uses the implicit loop to process observations in a data set, you can use the automatic variable _N_ in an IF statement to process the LOG4SAS_APPENDER function during the first DATA step iteration:

if _n_ = 1 then 
   do;
      rc=log4sas_appender("myAppenderName", "FileRefAppender", "fileref=myfiles");
      if rc ne 0 then do;
         msg = sysmsg();
         put msg;
         ABORT;
         end;
   end;