// PLAN-HTTPZ C2: the C->sx re-entry contract. A real OS thread enters
// sx through a `callconv(.c)` entry (which has NO implicit context),
// fabricates its own Context via `push Context.{ allocator = xx gpa }`,
// and calls default-conv sx code that allocates through it.
#import "modules/std.sx";

clib :: #library "c";
pthread_create :: (thread: *usize, attr: *void, start: (*void) -> *void callconv(.c), arg: *void) -> i32 extern clib;
pthread_join   :: (thread: usize, retval: **void) -> i32 extern clib;

entry :: (arg: *void) -> *void callconv(.c) {
    p : *i64 = xx arg;
    gpa := GPA.init();
    push Context.{ allocator = xx gpa } {
        s := concat("th", "read");      // allocate through the thread's OWN context
        if s.len == 6 { p.* = p.* * 2; }
    }
    return null;
}

main :: () -> i32 {
    v : i64 = 21;
    th : usize = 0;
    if pthread_create(@th, null, entry, xx @v) != 0 { print("create failed\n"); return 1; }
    pthread_join(th, null);
    if v != 42 { print("wrong result: {}\n", v); return 1; }
    print("pthread into sx ok: {}\n", v);
    return 0;
}