Getting the signature of a function

Getting the signature of a function

To write the C++ code that invokes the f_mult function, you need to obtain its method ID. The method ID is used to initialize the PBCallInfo structure and to invoke the function. There are two IPB_Session functions that return a method ID: GetMethodID, which takes a signature, and FindMatchingFunction, which takes a comma-separated list of arguments. You use the same functions when you call PowerScript from the code in your extension; see "Calling PowerScript from an extension".

If you want to use GetMethodID, you need a signature. This function is simple enough that you do not need a tool to obtain a signature—the signature is the string III, which indicates that the function returns an integer and takes two integers as arguments.

For more complicated functions, you can get the signature from the System Tree or with the pbsig125 tool.

Getting a signature from the System Tree

To get the signature of f_mult in the System Tree, expand nvo_mult, right-click on the f_mult function, and select Properties from the pop-up menu. The signature displays in the Properties dialog box in the Signature text box:

pbsig125 d:\pbls\loadpbvm.pbl

PB Object Name: loadpbvm
 
PB Object Name: nvo_mult
   public function integer f_mult (integer arg1,
      integer arg2)
      /*  III  */