Use the Trace module to selectively produce trace output
on a global and/or per-object basis for your application. You can
specify the types of trace output when an application is linked,
or dynamically (by using a debugger).
||You can also define your own trace function,
For example, you could define your own function to send traces
to a circular memory buffer.
The format of the trace output is determined by printf(...)-like
trace macros located in MPI library source. The trace macros are
of the form meiTrace#(mask, format, arg ...), where format
and the args determine the trace output, and where
# indicates the total number of arguments following the format
argument (because macros cannot take variable numbers of arguments).
The placement and content of the meiTrace(...) macros in
the MPI library source is the responsibility of whomever maintains
the library. Because trace can be added as desired, it is often
useful to leave trace statements in the library source code rather
than remove them, as is similarly done with debug printf(...) statements.
It is also useful to define per-object trace output types so that
the volume of trace output is set to a manageable level.
The Trace module interface is declared in the XMP\include\trace.h
header file. In order for your application to use Trace functions,
you must build your application with the MEI_TRACE conditional-compile
To install trace, simply install the DLL for either the Debug or
DebugSingle configuration. The Debug and DebugSingle configurations
of the MPI library are built with the MEI_TRACE compile-time symbol
||Debug and DebugSingle are the only
MPI library configurations that will produce trace output.
By default, trace output is sent to standard error. However, to
send trace output to a file, your application can call the meiTraceFile(char
To obtain the current global trace mask, call meiTraceGet(...).
To modify the global trace mask, call meiTraceSet(...).
To obtain an object's trace mask, call meiObjectTraceGet(...)
(defined in stdmei.h).
To modify an object's trace mask, call meiObjectTraceSet(...).