Returns a bit mask of recommended backends for current platform

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- Returns a bit mask of recommended backends for current platform

# Ev::recommendedBackends

(PECL ev >= 0.2.0)

Ev::recommendedBackends — Returns a bit mask of recommended backends for current platform

### Description

final public static Ev::recommendedBackends(): int

Returns the set of all backends compiled into this binary of `libev` and also recommended for this platform, meaning it will work for most file descriptor types. This set is often smaller than the one returned by ev_supported_backends() , as for example `kqueue` is broken on most `BSD` systems and will not be auto-detected unless it is requested explicitly. This is the set of backends that `libev` will probe no backends specified explicitly.

### Parameters

This function has no parameters.

### Return Values

Returns a bit mask which can containing backend flags combined using bitwise OR operator.

### Examples

Example #1 Embedding one loop into another

    <?php
    /*
    * Try to get an embeddable event loop and embed it into the default event loop.
    * If it is impossible, use the default
    * loop. The default loop is stored in $loop_hi, while the embeddable loop is
    * stored in $loop_lo(which is $loop_hi in the case no embeddable loop can be
    * used).
    *
    * Sample translated to PHP
    * http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod#Examples_CONTENT-9
    */
    $loop_hi = EvLoop::defaultLoop();
    $loop_lo = NULL;
    $embed   = NULL;

    /*
    * See if there is a chance of getting one that works
    * (flags' value of 0 means autodetection)
    */
    $loop_lo = Ev::embeddableBackends() & Ev::recommendedBackends()
     ? new EvLoop(Ev::embeddableBackends() & Ev::recommendedBackends())
     : 0;

    if ($loop_lo) {
     $embed = new EvEmbed($loop_lo, function () {});
    } else {
     $loop_lo = $loop_hi;
    }
    ?>

### See Also

- EvEmbed
- Ev::embeddableBackends() - Returns the set of backends that are embeddable in other event loops
- Ev::supportedBackends() - Returns the set of backends supported by current libev configuration
- Backend flags
- Examples