Handling Function Results

The following conventions are used for returning function result values.

  • Ordinal results are returned, when possible, in a CPU register. Bytes are returned in AL, words are returned in AX, and double-words are returned in EAX.
  • Real results are returned in the floating-point coprocessor's top-of-stack register (ST(0)). For function results of type Currency, the value in ST(0) is scaled by 10000. For example, the Currency value 1.234 is returned in ST(0) as 12340.
  • For a string, dynamic array, method pointer, or variant result, the effects are the same as if the function result were declared as an additional var parameter following the declared parameters. In other words, the caller passes an additional 32-bit pointer that points to a variable in which to return the function result.
  • Int64 is returned in EDX:EAX.
  • Pointer, class, class-reference, and procedure-pointer results are returned in EAX.
  • For static-array, record, and set results, if the value occupies one byte it is returned in AL; if the value occupies two bytes it is returned in AX; and if the value occupies four bytes it is returned in EAX. Otherwise, the result is returned in an additional var parameter that is passed to the function after the declared parameters.
Project Management Made Easy

Project Management Made Easy

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