futex(2)

DESCRIPTION

Waits on or wakes threads sharing a user word.

SYNOPSIS

long futex(uint32_t *address, uint32_t operation, uint32_t value);

RETURN VALUE

• Returns a non-negative result on success. Negative values are ABI errno codes.

ERRORS

• -EAGAIN
  • The futex value changed or the waiter table is full.
• -EFAULT
  • The futex word is not accessible userspace memory.
• -EINVAL
  • The operation is unknown.
• -ENOSYS
  • A timeout was requested but is not implemented.

ABI

Arguments enter through the direct syscall ABI; validation is performed before entering the process subsystem.