tt_ptype_opnum_callback_add(3)

NAME
tt_ptype_opnum_callback_add - return a callback if two opnums are equal

SYNOPSIS
#include <Tt/tt_c.h>

Tt_status tt_ptype_opnum_callback_add(const char *ptid,
	int opnum,
	Tt_message_callback f);

DESCRIPTION
The tt_ptype_opnum_callback_add() function returns a callback if the specified opnums are equal. The callback is defined in <Tt/tt_c.h>.

When a message is delivered because it matched a pattern derived from a signature in the named ptype with an opnum equal to the specified one, the given callback is run in the usual ToolTalk way.

The ptid argument is the identifier of the ptype involved in this operation. The opnum argument is the opnum of the specified ptype. The f argument is the message callback to be run.

RETURN VALUE
Upon successful completion, the tt_ptype_opnum_callback_add() function returns the status of the operation as one of the following Tt_status values:

    The operation completed successfully.
    The specified process type is not the name of an installed process type.
    The pointer passed does not point to an object of the correct type for this operation.
    The ttsession(1) process is not running and the ToolTalk service cannot restart it.

APPLICATION USAGE
The tt_ptype_opnum_callback_add() function will only be called for messages delivered by virtue of matching handler signatures. The callback cannot be called for observer signatures because the observer ptype is not recorded in the incoming message.

SEE ALSO
Tttt_c(5).