| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
System.PosixCompat.Unistd
Contents
Description
This module makes the operations exported by System.Posix.Unistd
available on all platforms. On POSIX systems it re-exports operations from
System.Posix.Unistd, on other platforms it emulates the operations as far
as possible.
System environment
getSystemID :: IO SystemID #
Sleeping
Sleep for the specified duration (in seconds). Returns the time remaining (if the sleep was interrupted by a signal, for example).
GHC Note: threadDelay is a better choice. Since GHC
uses signals for its internal clock, a call to sleep will usually be
interrupted immediately. That makes sleep unusable in a program compiled
with GHC, unless the RTS timer is disabled (with +RTS -V0). Furthermore,
without the -threaded option, sleep will block all other user threads.
Even with the -threaded option, sleep requires a full OS thread to
itself. threadDelay has none of these shortcomings.
Sleep for the specified duration (in microseconds).
GHC Note: threadDelay is a better choice.
Without the -threaded option, usleep will block all other user
threads. Even with the -threaded option, usleep requires a
full OS thread to itself. threadDelay has
neither of these shortcomings.