Display help information identified by a topic path


int PtHelpTopic( char *topic );




PtHelpTopic() tells the Helpviewer to display the help text located by the given topic path.

PtHelpTopic() spawns the Helpviewer if it isn't running, or sends a message to the Helpviewer if it is. Using this function, a Photon application can respond to a help request from the user by telling the Helpviewer to display the relevant help information.

If the topic path is relative (i.e. it doesn't start with a /), it's appended to the root topic path specified in an earlier call to PtHelpTopicRoot().


0 on success, or -1 if the Helpviewer couldn't be found or spawned.

Note: PtHelpTopic() returns immediately, before the help topic has been displayed.


The following example shows a fragment from a hypothetical application built using PhAB. This application first sets up a topic root for all help requests; it then displays help for a particular part of the application in response to a callback (which could be attached to a hotkey, for example).

#include <Pt.h>

int main( void )
       "/Photon microGUI/Programmer's Guide/Introduction" );

int HelpCallback( PtWidget_t * widget, ApInfo_t * apinfo, 
                  PtCallbackInfo_t * cbinfo )
    if( widget == ABW_Concepts )
        PtHelpTopic( "Widget concepts" );
    return( Pt_CONTINUE );



Interrupt handler No
Signal handler No
Thread No

See also:

PtHelpQuit(), PtHelpSearch(), PtHelpTopicRoot(), PtHelpTopicTree(), PtHelpUrl(), PtHelpUrlRoot()

Context-Sensitive Help chapter of the Photon Programmer's Guide

helpviewer in the QNX Neutrino Utilities Reference.