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The Axis C++ Trace Guide
This documents describes the trace facilities within Axis C++, how to enable them and how to make use of the produced trace.
To aid the development team in understanding the problems of users, the Axis C++ engine has been instrumented with trace.
Enabling runtime trace
Trace is enabled at runtime by adding the following to axiscpp.conf:
ClientLogPath:<path to log file>
Reading runtime trace
The Axis C++ runtime trace is produced in a format compatible with the Trace Analyzer for WebSphere Application Server, which is available from here:
However, it is also possible to use any text editor. Each line is made up of the following columns:
So, a typical entry would be:
[27/03/2006 16:21:48:945 Time] 4220 AxisConfig > getAxisConfProperty @00376358, <....>
Some other things to watch for are:
One shortcoming of the runtime trace is that it only begins tracing after the configuration file has been loaded and the ClientLogPath entry read. This means any problems that occur before this, for example while reading the configuration file, are missed. To overcome this the Axis C++ engine has also been instrumented with startup trace, this starts tracing at the first call into the Axis engine and everything up to the point at which runtime trace starts.
Startup trace uses the same formatting as the runtime trace.
Enabling startup trace
Startup trace is enabled by setting the following environment variable:
AXISCPP_STARTUP_TRACE=<path to startup log file>
Interesting Trace Entries
Here are a few entries well worth looking for when you first receive a trace file.
Check lines in the trace file immediately preceding the entry for ~Stub, as this is typically the first method run following a SIGSEGV.
Check any exception entries, which is indicated by an X in the 3rd column. These actually indicate that an exception has been caught. If you see @<number> this indicates which catch block, if more than one present in the current method. You can use this, along with the trace lines immediately preceding, to determine fairly closely exactly where the trace was thrown. You will also see trace entries for the exception constructor if it is an Axis C++ exception.
The entry trace for operator<< on HTTPChannelshows the message that will sent on the wire. Although the HTTP Header and SOAP message tend to be in seperate calls to this method. This allows for diagnosis of some problems with the message, without requiring the use of a tcp/ip monitoring tool.