C file functions in QB64 ???

[DSMan195276]

There's a couple issues. The big one is the lack of

Byval

on your

file_ptr

parameters to

fprintf()

and

fclose()

. Pass-by-reference is the default so QB64 will actually pass the address of the

_Offset

rather than the

_Offset

value itself, leading to the explosions you're encountering. If you instead use

byval file_ptr As _Offset

then it might work.

The other issues is the types in the C++ function definitions.

fprintf()

and

fclose()

take a

FILE *

as their first argument, but an

_Offset

is an

intptr_t

so you cannot pass that as a

FILE *

without a cast (and there's no way to insert the cast as QB64 won't do it for you). The solution here is to use either

Declare Dynamic Library

or (preferably)

Declare CustomType Library

, both of those cause QB64 to generate its own C++ definitions for the functions listed in the

Declare Library

section based on the types you define, so the types you provide will always match. The big catch with this is that it also means there will be no type-checking by C++ to ensure you're actually passing the right thing, so it's best to use regular

Declare Library

for any functions where it's possible for you to provide the correct types directly (like

fopen()

).