Generic interface with subroutine and function

8

This explains the reason the overloading is permitted in C++. Both are functions, and since the return argument can be ignored, you can also call them the same way:

foo(a1,a2);     // returns void, no error can occur
foo(b1,b2,b3);  // returns int error flag, but we discard it

thus making the functions suitable to use in the same overload set.

But in Fortran, this might make you raise an eyebrow:

call foo(a1,a2)      ! Huh, why doesn't foo return something?
stat = foo(b1,b2,b3)

Instead we adopt the Python zen “Explicit is better than implicit” and use the rename at import facility:

use baz, only: foo
use bar, only: foo_always_safe => foo

call foo_always_safe(a1, a2)
stat = foo(b1,b2,b3)
if (stat /= 0) error stop "foo failed"
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