char *tttk_op_string( Tttk_op op};
The tttk_op_string() function returns string for the operation op if successful; otherwise, this function returns zero.
Use the tt_free() function to free the string returned.
Tttk_op tttk_string_op( const char * opstring );
The tttk_string_op() function returns a string containg the operation for the specified string. On error, this function returns TTDT_OP_NONE.