void
runtime·cgocall(void (*fn)(void*), void *arg)
{
Defer d;
if(m->racecall) {
runtime·asmcgocall(fn, arg);
return;
}
if(!runtime·iscgo && !Windows)
runtime·throw("cgocall unavailable");
if(fn == 0)
runtime·throw("cgocall nil");
if(raceenabled)
runtime·racereleasemerge(&cgosync);
// Create an extra M for callbacks on threads not created by Go on first cgo call.
if(runtime·needextram && runtime·cas(&runtime·needextram, 1, 0))
runtime·newextram();
m->ncgocall++;
/*
* Lock g to m to ensure we stay on the same stack if we do a
* cgo callback. Add entry to defer stack in case of panic.
*/
runtime·lockOSThread();
d.fn = &endcgoV;
d.siz = 0;
d.link = g->defer;
d.argp = (void*)-1; // unused because unlockm never recovers
d.special = true;
d.free = false;
g->defer = &d;
m->ncgo++;
/*
* Announce we are entering a system call
* so that the scheduler knows to create another
* M to run goroutines while we are in the
* foreign code.
*
* The call to asmcgocall is guaranteed not to
* split the stack and does not allocate memory,
* so it is safe to call while "in a system call", outside
* the $GOMAXPROCS accounting.
*/
runtime·entersyscall();
runtime·asmcgocall(fn, arg);
runtime·exitsyscall();
if(g->defer != &d || d.fn != &endcgoV)
runtime·throw("runtime: bad defer entry in cgocallback");
g->defer = d.link;
endcgo();
}
// The main goroutine.
void
runtime·main(void)
{
// Lock the main goroutine onto this, the main OS thread,
// during initialization. Most programs won't care, but a few
// do require certain calls to be made by the main thread.
// Those can arrange for main.main to run in the main thread
// by calling runtime.LockOSThread during initialization
// to preserve the lock.
runtime·lockOSThread();
// From now on, newgoroutines may use non-main threads.
setmcpumax(runtime·gomaxprocs);
runtime·sched.init = true;
scvg = runtime·newproc1((byte*)runtime·MHeap_Scavenger, nil, 0, 0, runtime·main);
scvg->issystem = true;
main·init();
runtime·sched.init = false;
runtime·unlockOSThread();
// The deadlock detection has false negatives.
// Let scvg start up, to eliminate the false negative
// for the trivial program func main() { select{} }.
runtime·gosched();
main·main();
if(raceenabled)
runtime·racefini();
runtime·exit(0);
for(;;)
*(int32*)runtime·main = 0;
}
