Options for Logging

There are two ways in which an application can write messages to the SNA Server log files:

• Use the SNA Server DMOD (dynamic access module) logging macros presented in the following topic.
• Use the LOG_MESSAGE common service verb.

Both of these options use log message files formatted with the OS/2 utility MKMSGF. A log message file contains a set of messages that are referenced by a message number. If a component wishes to log an error, it specifies the appropriate message number to extract the text from the message file, rather than including the message text within the component.

SNA Server has one message file that is used for all its error and audit logging. The messages in this file are available for both of the preceding options. See the Microsoft SNA Server Reference for a list of all the SNA Server error and audit log messages and their meanings.

If extra messages are required, there are two options:

• The messages COM0393 and COM0394 are provided as generic log messages for use by emulators. Each takes two parameters, both of which are text strings: the first is an identifier for the specific emulator that logged the message, and the second can contain any data or parameters to be logged. The difference between these messages is the level at which they are logged; COM0393 is a level 10 information message, while COM0394 is a warning message that should be used to report error conditions. See SNA Server DMOD Logging Macros for more information on message severity levels.
• A second message file can be created, which is then specified as one of the parameters on the LOG_MESSAGE verb. This cannot be used with the logging macros.

It is recommended that you use the SNA Server logging macros (with the SNA Server emulator log messages if a suitable message is available, or with the generic messages COM0393 and COM0394) rather than the LOG_MESSAGE verb. LOG_MESSAGE does not provide control over the severity level at which messages are logged (all messages are logged at level 12 in the error log file); it is primarily intended for user applications such as APPC TPs.

The following topics explain the use of the SNA Server logging macros and the LOG_MESSAGE common service verb.