Linux system call getifaddr c++

in my c++ application I've wrriten t开发者_如何学运维his code:

struct ifaddrs *ifap;

if (0 != getifaddrs(&ifap)) {
    error = errno;
    return -1;
}

addresses.clear();
for (struct ifaddrs *ifa = ifap; ifa; ifa = ifa->ifa_next) {
    sockaddr *s=ifa->ifa_addr;
    PRINT(" LocalIP sockaddr %u.%u.%u.%u \n",s->sa_data[2],s->sa_data[3],s->sa_data[4],s->sa_data[5]);}

when I debug the print I see that when I have static ip like 10.0.0.12 it prints it correct. but ip from DHCP like 192.168.14.12 it prints it "-64.-88.14.12"

how can I solve this issue?

10x

Change %d's to %hhu's.

%d is signed integer. %u is unsigned integer. %hhu is unsigned char.

This code shows why:

#include <cstdio>

int main()
{
        char i = 192;
        printf("%u, %hhu, %d", i,i,i);
}

Output: 4294967232, 192, -64

Seems like it's trying to print bytes as signed. Try using %u instead of %d inside IP address.