PHP扩展开发：如何编写跨平台兼容的自定义函数？

<?php
#ifdef PHP_WINDOWS

/**
 * Retrieve the size of a Windows file in bytes.
 *
 * @param string $path The path to the file.
 *
 * @return int The size of the file in bytes.
 */
function get_file_size($path)
{
    if (!file_exists($path)) {
        throw new InvalidArgumentException("File not found: $path");
    }

    $size = filesize($path);

    return $size !== false ? $size : 0;
}
#else

/**
 * Retrieve the size of a file in bytes.
 *
 * @param string $path The path to the file.
 *
 * @return int The size of the file in bytes.
 */
function get_file_size($path)
{
    if (!file_exists($path)) {
        throw new InvalidArgumentException("File not found: $path");
    }

    // In non-Windows environments, use the `stat()` function to determine file size.

    $stats = stat($path);
    if ($stats !== false) {
        return $stats['size'];
    } else {
        return 0;
    }
}
#endif