# Module Netsys_pollset_generic

    module Netsys_pollset_generic: sig .. end

Returns a good standard implementation of pollset for this platform. It will be good for cases where only a small to medium number of descriptors is watched (several hundred should be ok). It is no problem when the pollset lives only for a short time. Also, it is not strictly necessary to call the `dispose` method after use.

On POSIX platforms, this returns a `Netsys_pollset_posix.poll_based_pollset`.

On Win32, this returns `Netsys_pollset_win32.pollset` in single-threaded programs, and a `Netsys_pollset_win32.threaded_pollset` in multi-threaded programs. Note that Win32 restricts the number of descriptors that can be watched per thread to 64. The `threaded_pollset` version overcomes this limit, but it is only available if your program is compiled for multi-threading. Because of this, it may be useful to enable multi-threading for your program even when your code does not make use of it otherwise.

    val standard_pollset : unit -> Netsys_pollset.pollset

Returns a good standard implementation of pollset for this platform. It will be good for cases where only a small to medium number of descriptors is watched (several hundred should be ok). It is no problem when the pollset lives only for a short time. Also, it is not strictly necessary to call the `dispose` method after use.

On POSIX platforms, this returns a `Netsys_pollset_posix.poll_based_pollset`.

On Win32, this returns `Netsys_pollset_win32.pollset` in single-threaded programs, and a `Netsys_pollset_win32.threaded_pollset` in multi-threaded programs. Note that Win32 restricts the number of descriptors that can be watched per thread to 64. The `threaded_pollset` version overcomes this limit, but it is only available if your program is compiled for multi-threading. Because of this, it may be useful to enable multi-threading for your program even when your code does not make use of it otherwise.

    val performance_pollset : unit -> Netsys_pollset.pollset

Returns the best available pollset on this platform for high performance servers that have to deal with many different file descriptors. Note that this pollset may have higher initial costs, and may not be suitable for cases where pollsets live only for a short time. Also, make sure the `dispose` method is called after use.

Currently, this is the same as `standard_pollset`, because no better implementations exist. In the future, `performance_pollset` will use kernel-based polling on some OS ("epoll", "kqueue", "/dev/poll", etc.)

    val select_emulation : Netsys_pollset.pollset ->
           Unix.file_descr list ->
           Unix.file_descr list ->
           Unix.file_descr list ->
           float -> Unix.file_descr list * Unix.file_descr list * Unix.file_descr list

`let select = select_emulation pset`: Returns a function with the same meaning as `Unix.select`. It is emulated on top of `pset`.

Using the function is only recommended when the lists of file descriptors are short. Long lists impose a big performance penalty.

Unlike `Unix.select` the descriptors may be returned in any order.