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#include <util/system/platform.h>
#ifdef _linux_
#include <sys/syscall.h>
#include <linux/futex.h>
#if !defined(SYS_futex)
#define SYS_futex __NR_futex
#endif
#endif
#include <errno.h>
#include <util/system/yassert.h>
#include "futex_like.h"
#ifdef _linux_
namespace {
int futex(int* uaddr, int op, int val, const struct timespec* timeout,
int* uaddr2, int val3) {
return syscall(SYS_futex, uaddr, op, val, timeout, uaddr2, val3);
}
}
#endif
void TFutexLike::Wake(size_t count) {
Y_ASSERT(count > 0);
#ifdef _linux_
if (count > unsigned(Max<int>())) {
count = Max<int>();
}
int r = futex(&Value, FUTEX_WAKE, count, nullptr, nullptr, 0);
Y_VERIFY(r >= 0, "futex_wake failed: %s", strerror(errno));
#else
TGuard<TMutex> guard(Mutex);
if (count == 1) {
CondVar.Signal();
} else {
CondVar.BroadCast();
}
#endif
}
void TFutexLike::Wait(int expected) {
#ifdef _linux_
int r = futex(&Value, FUTEX_WAIT, expected, nullptr, nullptr, 0);
Y_VERIFY(r >= 0 || errno == EWOULDBLOCK, "futex_wait failed: %s", strerror(errno));
#else
TGuard<TMutex> guard(Mutex);
if (expected == Get()) {
CondVar.WaitI(Mutex);
}
#endif
}
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