Interlanguage Calls - Function Return Values

Functions pass their return values according to type:

• Pointers, enumerated types, and integral values (int, short, long, char, and unsigned types) of any length are returned, right-justified, in R3; long long values are returned in R3 and R4. (R3 in 64-bit mode)
• floats and doubles are returned in FP1; 128-bit long doubles are returned in FP1 and FP2.
• Calling functions supply a pointer to a memory location where the called function stores the returned value.
• long doubles are returned in R1 and R2.

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