Re: [lwip-users] Timeout wraparound bug

[Sergio R. Caprile]

Nope, the difference will be preserved by type promotion, unless the 
wrap around occurs more than once between calls or the counter counted 
more than half length counts (which also includes the former...).
Are you calling frequently enough sys_check_timeouts() ?
You should (read 'must').

Otherwise, you have a compiler problem, try this:
#include <stdio.h>
#include <stdint.h>

uint32_t now = 1;
uint32_t timeouts_last_time = 0xFFFFFFFF;

main()
{
uint32_t diff = now - timeouts_last_time;

        printf("%u\n",diff);
        if((now - timeouts_last_time) > 2)
                printf("Oops\n");
        else
                printf("OK\n");
}

$ ./td
2
OK