diff --git a/src/modem.c b/src/modem.c index 70d6b81..6f7caf2 100644 --- a/src/modem.c +++ b/src/modem.c @@ -484,7 +484,8 @@ int gsm_modem_send_message(GSMModem * gsmm, char const * number, GSM_ERROR_MESSAGE_SEND_FAILED, NULL); } snprintf(buf2, len2, "%s%02lX%s%s%s%s%02lX%s\x1a", cmd2, - number[0] == '+' ? strlen(number) - 1 : strlen(number), + (unsigned long)((number[0] == '+') + ? strlen(number) - 1 : strlen(number)), addr, pid, dcs, vp, (unsigned long)strlen(text), sept); snprintf(buf1, len1, "%s%lu", cmd1, (len2 - 1) / 2); free(addr);