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:

        TT_OK   The operation completed successfully.

        TT_ERR_PTYPE
                The specified process type is not the name of an installed
                process type.

        TT_ERR_POINTER
                The pointer passed does not point to an object of the correct
                type for this operation.

        TT_ERR_NOMP
                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).