stream_set_blocking

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

stream_set_blocking — 为资源流设置阻塞或者阻塞模式

说明

stream_set_blocking(resource $stream, bool $enable): bool

为 stream 设置阻塞或者非阻塞模式。

此函数适用于支持非阻塞模式的任何资源流（常规文件，套接字资源流等）。

参数

stream: 资源流。
enable: 如果 enable 为 false，资源流将会被转换为非阻塞模式；如果是 true，资源流将会被转换为阻塞模式。该参数的设置将会影响到像 fgets() 和 fread() 这样的函数从资源流里读取数据。在非阻塞模式下，调用 fgets() 总是会立即返回；而在阻塞模式下，将会一直等到从资源流里面获取到数据才能返回。

返回值

成功时返回 true，或者在失败时返回 false。

注释

注意:
在 Windows 系统上，这对本地文件没有影响。Windows 不支持本地文件的非阻塞 IO。

参见

stream_select() - Runs the equivalent of the select() system call on the given arrays of streams with a timeout specified by seconds and microseconds

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Anonymous ¶

11 years ago

On Windows this function does not work with pipes opened with proc_open (https://bugs.php.net/bug.php?id=47918, https://bugs.php.net/bug.php?id=34972, https://bugs.php.net/bug.php?id=51800)

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MagicalTux at ookoo dot org ¶

18 years ago

When you use fwrite() on a non-blocking stream, data isn't discarded silently as t dot starling said.

Remember that fwrite() returns an int, and this int represents the amount of data really written to the stream. So, if you see that fwrite() returns less than the amount of written data, it means you'll have to call fwrite() again in the future to write the remaining amount of data.

You can use stream_select() to wait for the stream to be available for writing, then continue writing data to the stream.

Non-blocking streams are useful as you can have more than one non-blocking stream, and wait for them to be available for writing.