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LibPthread: Set errno in sem_trywait()

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Timur Sultanov 2022-02-16 21:23:24 +03:00 • committed by Linus Groh
parent 0a63461341
commit 15cce56411
1 changed files with 9 additions and 5 deletions
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14
Userland/Libraries/LibPthread/semaphore.cpp
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@ -93,15 +93,19 @@ int sem_trywait(sem_t* sem)
{ {
u32 value = AK::atomic_load(&sem->value, AK::memory_order_relaxed); u32 value = AK::atomic_load(&sem->value, AK::memory_order_relaxed);
u32 count = value & ~POST_WAKES; u32 count = value & ~POST_WAKES;
if (count == 0) if (count == 0) {
return EAGAIN; errno = EAGAIN;
return -1;
}
// Decrement the count without touching the flag. // Decrement the count without touching the flag.
u32 desired = (count - 1) | (value & POST_WAKES); u32 desired = (count - 1) | (value & POST_WAKES);
bool exchanged = AK::atomic_compare_exchange_strong(&sem->value, value, desired, AK::memory_order_acquire); bool exchanged = AK::atomic_compare_exchange_strong(&sem->value, value, desired, AK::memory_order_acquire);
if (exchanged) [[likely]] if (exchanged) [[likely]] {
return 0; return 0;
else } else {
return EAGAIN; errno = EAGAIN;
return -1;
}
} }
// https://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_wait.html // https://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_wait.html