Sending NAG C errors to the MessageSvc

Sending NAG C library errors to the GAUDI Message Service

The GaudiNagC package in the Gaudi software distribution contains classes to handle NAG C library errors within Gaudi. Please note that the current release only allows to create one instance of the GaudiErrorHandler class. The following steps are needed in order to use them in your algorithm:

Use the package in the requirements file:
use GaudiNagC v*
In your header file, declare a member variable to hold a pointer to the error handling object, e.g.:

class GaudiErrorHandler;

private
GaudiErrorHandler* m_handler;

Add the following to your implementation file:

Include the header file of the GaudiNagHandler class, which interfaces NAG errors to the Gaudi MessageSvc:

#include "GaudiNagC/GaudiNagHandler.h"

In the constructor, set the pointer to the error handling object to zero:

m_handler = 0;

In the algorithm's initialize() method, create a new GaudiErrorHandler object which will remember the address of the message service, and the name of your algorithm:

if( m_handler == 0 ) m_handler = new GaudiErrorHandler(messageService(), name());

Do not forget to delete this object in your destructor.....

Whenever you call a NAG C function that can return an error, use the syntax in the example below to declare an error handler:

g05cgc( istate, xstate, GaudiNagHandler::declareHandler(m_handler) );

The default behaviour of this service is given by the execute() method of the GaudiErrorHandler class. If you wish to have a different behaviour, you should write your own class derived from GaudiErrorHandler, reimplement the execute() method, then use your new class instead of GaudiErrorHandler.

The implementation of GaudiErrorHandler::execute() is shown below:

void GaudiErrorHandler::execute(char *string, int code, char *name) {

MsgStream log(messageSvc(), algName());
if (code != NE_NOERROR ) {
if( !strncmp( string, "NE", 2 )) {
     log << MSG::ERROR << " from " << name << " (NAG): " << string << endreq;
}
else {
     log << MSG::WARNING << " from " << name << " (NAG): " << string << endreq;
}
}
else {
    log << MSG::INFO << name << " (NAG) called successfully" << endreq;
}
}