Handler Characteristics

The basic requirements for subcommand, function, and system exit handlers are:

• REXX handlers must use the system linkage convention. Handler functions should be declared with the appropriate type definition from the REXXSAA.H include file:

  • RexxSubcomHandler
    
  • RexxFunctionHandler
    
  • RexxExitHandler
  
  A REXX handler must be packaged as either:

  • An exported routine within a Dynamic Link Library (DLL)
    
  • An entry point within an executable (EXE) module
  
  A handler must be registered with REXX before it can be used. REXX uses the registration information to locate and call the handler. For example, external function registration of a dynamic link library external function identifies both the dynamic link library and routine that contains the external function. Also note:

  • Dynamic link library handlers are global to the OS/2 system; any REXX program can call them.

  • EXE file handlers are local to the registering process; only a REXX program running in the same process as an EXE module can call a handler packaged within that EXE module.

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