process.py 文件源码

def _check_system_limits():
    global _system_limits_checked, _system_limited
    if _system_limits_checked:
        if _system_limited:
            raise NotImplementedError(_system_limited)
    _system_limits_checked = True
    try:
        import os
        nsems_max = os.sysconf("SC_SEM_NSEMS_MAX")
    except (AttributeError, ValueError):
        # sysconf not available or setting not available
        return
    if nsems_max == -1:
        # indetermine limit, assume that limit is determined
        # by available memory only
        return
    if nsems_max >= 256:
        # minimum number of semaphores available
        # according to POSIX
        return
    _system_limited = "system provides too few semaphores (%d available, 256 necessary)" % nsems_max
    raise NotImplementedError(_system_limited)