A simple "Hello, world" program using Mach threads.

mach_thread_test

#include <iostream>

#include <unistd.h>
#include <mach/mach.h>
#include <mach/mach_vm.h>
#include <mach/mach_error.h>
#include <mach/mach_init.h>
#include <mach/mach_types.h>
#include <mach/mach_traps.h>
 
#include <mach/task.h>
#include <mach/thread_act.h>
#include <mach/thread_policy.h>
#include <mach/i386/thread_status.h>
 
void check(kern_return_t err)
{
	if (err == KERN_SUCCESS) return;
	std::cerr << mach_error_string(err) << std::endl;
	exit(EXIT_FAILURE);
}

void test()
{
	// pthread_set_self?
	write(1, "Hello, world!\n", 14);
	check(thread_terminate(mach_thread_self()));
}
 
int main()
{
	task_t task        = mach_task_self();
	int stack_size     = 65536;
	vm_address_t stack = 0;
	check(mach_vm_allocate(task, (mach_vm_offset_t*)&stack, stack_size,
		VM_FLAGS_ANYWHERE));
	
	x86_thread_state64_t state;
	mach_msg_type_number_t count = x86_THREAD_STATE64_COUNT;
	vm_address_t stack_ptr = stack + stack_size / 2 - 8;
 
	state.__rip = (uintptr_t)test;
	state.__rsp = (uintptr_t)stack_ptr;
	state.__rbp = (uintptr_t)stack_ptr;

	auto thread = thread_t{};
	check(thread_create_running(task, x86_THREAD_STATE64,
		(thread_state_t)&state, x86_THREAD_STATE64_COUNT, &thread));
 
	// Give the thread a chance to run.
	sleep(1);
	printf("Done.");
}