Faspstream Manager C/C++ API  3.6.1
A C and C++ language interface to basic streaming over the fasp protocol
/home/jeff/Documents/Code/3.6.1/include/Constants.h

Function type definition for registering a logging callback

Provide your own logging function by registering a funcion of this type (void return, const char* argument) with the faspstream client or server.

The default implementation looks like this:

static void log_function( char const *s ) {
    fprintf( stderr, "%s\n", s );
}