chdir

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

chdir — Change directory

Description

chdir(string $directory): bool

Changes PHP's current directory to directory.

Parameters

directory: The new current directory

Return Values

Returns true on success or false on failure.

Errors/Exceptions

Throws an error of level E_WARNING on failure.

Examples

Example #1 chdir() example

<?php

// current directory
echo getcwd() . "\n";

chdir('public_html');

// current directory
echo getcwd() . "\n";

?>

The above example will output something similar to:

/home/vincent
/home/vincent/public_html

Notes

Caution

If the PHP interpreter has been built with ZTS (Zend Thread Safety) enabled, any changes to the current directory made through chdir() will be invisible to the operating system. All built-in PHP functions will still respect the change in current directory; but external library functions called using FFI will not. You can tell whether your copy of PHP was built with ZTS enabled using php -i or the built-in constant PHP_ZTS.

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User Contributed Notes 1 note

down

nesk at xakep dot ru ¶

3 years ago

When working with FFI under a PHP ZTS environment, there is no standard way to change the directory with libraries (dll/so/dylib/etc), so to get around this problem, you should use something like this polyfill:

<?php

$directory = 'path/to/libraries';

switch (\PHP_OS_FAMILY) {
    case 'Windows':
\FFI::cdef('extern unsigned char SetDllDirectoryA(const char* lpPathName);', 'kernel32.dll')
            ->SetDllDirectoryA($directory)
        ;
        break;

    case 'Linux':
    case 'BSD':
\FFI::cdef('int setenv(const char *name, const char *value, int overwrite);')
            ->setenv('LD_LIBRARY_PATH', $directory, 1)
        ;
        break;

    case 'Darwin':
\FFI::cdef('int setenv(const char *name, const char *value, int overwrite);')
            ->setenv('DYLD_LIBRARY_PATH', $directory, 1)
        ;
        break;
}

?>