Most probably this error comes from a copy/paste problem from another sample file. I mean, app_perror
is defined on every sample file to show possible errors in different ways depending on test running, this is, for solving your error, you would need to add its definition, initially, at the beginning, for example, before logging_on_rx_msg
:
static void app_perror(const char *sender, const char *title, pj_status_t status)
{
char errmsg[PJ_ERR_MSG_SIZE];
pj_strerror(status, errmsg, sizeof(errmsg));
PJ_LOG(1,(sender, "%s: %s", title, errmsg));
}