Interlanguage Calls - Type Encoding and Checking

Detecting errors before a program is run is a key objective of IBM C and C++ Compilers. Runtime errors are hard to find, and a many are caused by mismatching subroutine interfaces or conflicting data definitions.

IBM C and C++ Compilers uses a scheme for early detection that encodes information about all external symbols (data and programs). If the -qextchk option has been specified, this information about external symbols is checked at bind or load time for consistency.

The Assembler Language Reference for the AIX RISC System/6000 book describes the following details of the Subroutine Linkage Convention:

• Register usage (general-purpose, floating-point, and special-purpose registers)
• Stack
• The calling routine's responsibilities
• The called routine's responsibilities

Interlanguage Calling Conventions
Corresponding Data Types
Using the Subroutine Linkage Conventions in Interlanguage Calls
Sample Program: C Calling Fortran