Extern.md

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Extern attribute

#extern can be used to declare functions or variable from libc
Only extern function can be Variadic.

Function

Same as regular function declaration, but without argument names and may be variadic.

#extern
abs :: (i32) -> i32;

#extern
fprintf :: (*FILE, *char, ...);

Global variables

Same as regular global variable declaration.

FILE :: struct {}

#extern
stdout: *FILE;

Multiline

Due to different declaration syntax #extern not working with #expand. Now it applicable to block with expanded.

#extern {
    abs :: (i32) -> i32;
    printf :: (*char, ...);
}

example

Warning: stdout not declared on some platforms.

// we don't care about FILE layout and just use *FILE
FILE :: struct {}

#extern
stdout: *FILE;

#extern
abs :: (i32) -> i32;

#extern
fprintf :: (*FILE, *char, ...);

main :: () -> i32 {
    fprintf(stdout, "Hello user %d", abs(-765));
    return 0;
}