PHP_SAFE_MAX_FD   201 main/php_network.h # define PHP_SAFE_MAX_FD(m, n)		do { if (n + 1 >= FD_SETSIZE) { _php_emit_fd_setsize_warning(n); }} while(0)
PHP_SAFE_MAX_FD   206 main/php_network.h # define PHP_SAFE_MAX_FD(m, n)		do { if (m >= FD_SETSIZE) { _php_emit_fd_setsize_warning(m); m = FD_SETSIZE - 1; }} while(0)