// libcall.rg — calling external C functions at link time (@libcall)
//
// `@libcall("symbol", .{args...})` binds a symbol against libc or any
// library named with `-l`/`-L`, resolved by the system linker into a native
// executable built with `rinne build --native`. It's available ONLY in the
// linked native build (the freestanding `--no-libc` path has no linker).
// Up to six integer args; the returned `int` lands in `rax` and can feed
// `return`.
//
// Build (links libc implicitly — `abs` lives there):
//   rinne build --native examples/libcall.rg
//   ./examples/libcall.rgx && echo "exit=$?"     # -> 7
//
// To call a function from YOUR own C library, compile one first, e.g.
//   cat > /tmp/triple.c <<'EOF'
//   int triple(int x) { return x * 3; }
//   EOF
//   cc -shared -fPIC -o /tmp/libtriple.so /tmp/triple.c
//   rinne build --native examples/libcall.rg -L /tmp -ltriple
//
//   (uncomment the triple line below and the immutables above main; uncomment
//   nothing else — but note only ONE return runs. Swap the active return.)

fn main() int {
    // libc `abs`: pass one integer arg (-7), get the int result back (7).
    return @libcall("abs", .{-7});
}

// For a function from your own library (the -ltriple build above), uncomment
// the main below INSTEAD — a script has exactly one `main`:
// fn main() int {
//     return @libcall("triple", .{7});    // -> 21
// }