Advanced Programming Guide

7.2 Using Compiled Code in Maple • 317/* main entry point - MWRAP_add */ALGEB myAdd( MKernelVector kv, ALGEB fn_args ){INTEGER32 a1; /* INTEGER32 => int (defined in mpltable.h) */INTEGER32 a2;INTEGER32 r;if( MapleNumArgs(kv,fn_args) != 2 )MapleRaiseError(kv,"Incorrect number of arguments");/* convert from Maple integer to C int */a1 = MapleToInteger32(kv,((ALGEB*)fn_args)[1]);/* convert from Maple integer to C int */a2 = MapleToInteger32(kv,((ALGEB*)fn_args)[2]);r = a1 + a2;}return( ToMapleInteger(kv,(long) r) );This program first verifies if the Maple function call passed exactlytwo arguments. It then converts the two arguments to hardware integersand adds them. The result is converted to a Maple integer and returned.This program can be compiled into a DLL using your favorite C compiler.Ensure that you link with the Maple API shared library. The DLLcan be placed into the Maple bin.$SYSTEM directory, or somewhere elsein the PATH. When using DLLs outside of bin.$SYSTEM directory, youmay need to specify the full path to the DLL in the LIB argument todefine_external. UNIX developers may need to set their load-librarypath.Table 7.4 on page 340 lists the Maple API Libraries for C and Fortran.After compiling the DLL, the function can be used in Maple. No typedesciptors are needed in the define_external call since Maple does noconversion on arguments passed to the custom wrapper.> myAdd := define_external(’myAdd’,’MAPLE’,’LIB’=> "myAdd.dll"):> myAdd(2,3);5