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    posix_isatty

    (PHP 4, PHP 5, PHP 7, PHP 8)

    posix_isatty — Determine if a file descriptor is an interactive terminal

    说明

    posix_isatty(resource|int $file_descriptor): bool

    Determines if the file descriptor file_descriptor refers to a valid terminal type device.

    参数

    file_descriptor

    The file descriptor, which is expected to be either a file resource or an int. An int will be assumed to be a file descriptor that can be passed directly to the underlying system call.

    返回值

    Returns true if file_descriptor is an open descriptor connected to a terminal and false otherwise.

    更新日志

    版本 说明
    8.3.0 Type error E_WARNINGs are now raised for integer coercions following the usual PHP type coercion semantics.

    参见

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    User Contributed Notes 2 notes

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    1
    hfuecks at phppatterns dot com
    20 years ago
    Can be useful to determine whether output is being piped elsewhere, for PHP shell scripts, for example;

    #!/usr/local/bin/php
    <?php
    if ( !posix_isatty(STDOUT) ) {
            fwrite(STDOUT, "Invalid TTY\n");
        exit(    2);
    }
    fwrite(STDOUT, "Enter you name\n");
    $name = fgets(STDIN);
    fwrite(STDOUT,"Hello $name\n");
    exit(    0);
    ?>

    If this script is like:

    script.php > outfile

    outfile will contain "Invalid TTY"
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    0
    KEINOS
    3 years ago
    It's quite complicated to understand its movements. But it determines if the file_descriptor is open AND connected to a terminal.

    Thus, while receiving data from the STDIN, for example, it will return false.

    This move is useful to optionally pipe STDIN to a PHP script, to avoid hanging when nothing is from STDIN.

    <?php

    // Simply echoes the contents from STDIN if any
    // and "no stdin" if not.
    echo (posix_isatty(STDIN)) ? 'no stdin' . PHP_EOL : file_get_contents('php://stdin');
    ?>
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