tt_message_arg_add(3)

NAME
     tt_message_arg_add - add a new argument to a message object

SYNOPSIS
     #include <Tt/tt_c.h>
     Tt_status tt_message_arg_add(Tt_message m,
                                  Tt_mode n,
                                  const char *vtype,
                                  const char *value);

DESCRIPTION
     The tt_message_arg_add() function adds a new argument to a message
     object.

     The application must add all arguments before the message is sent.  To
     change existing argument values, the application must use only modes
     TT_OUT or TT_INOUT.

     Adding arguments when replying to a message produces undefined results.

     The m argument is the opaque handle for the message involved in this
     operation.  The n argument specifies who (sender, handler, observers)
     writes and reads a message argument.  The following modes are defined:

        TT_IN   The argument is written by the sender and read by the handler
                and any observers.

        TT_OUT
                The argument is written by the handler and read by the sender
                and any reply observers.

        TT_INOUT
                The argument is written by the sender and the handler and read
                by all.

     The vtype argument describes the type of argument data being added.  The
     value argument is the contents for the message argument attribute.  The
     application can use NULL either for values of mode TT_OUT, or if the
     value is to be filled in later with one of the following:

          tt_message_arg_val_set(3)
          tt_message_barg_val_set(3)
          tt_message_iarg_val_set(3)

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

        TT_OK   The operation completed successfully.
        TT_ERR_MODE
                The specified Tt_mode is invalid.

        TT_ERR_NOMP
                The ttsession(1) process is not running and the ToolTalk
                service cannot restart it.

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

SEE ALSO
     Tttt_c(5), tt_message_arg_val_set(3), tt_message_barg_add(3),
     tt_message_iarg_add(3).