Description:
------------
Hello!

We've checked your code with AppChecker static analyzer and found possible bug:

https://github.com/php/php-src/blob/e0f68ae1441bac063e2a72b980f1ddfee596ea25/sapi/phpdbg/phpdbg_io.c#L352

PHPDBG_API void phpdbg_close_socket(int sock) {
    if (socket >= 0) {
#ifdef _WIN32
        closesocket(sock);
#else
        shutdown(sock, SHUT_RDWR);
        close(sock);
#endif
    }
}

socket is a function. It seems suspicious to compare pointer with '0'. Maybe variable sock must be used instead?

Possible defect was found by Echelon Team with [AppChecker static analyzer](https://cnpo.ru/en/solutions/appchecker.php)