set local time from timezone offset in seconds

Question

I have the timezone offset in seconds from a weather api. Would like to set the local time using this offset. #include <stdio.h> #include <time.h>

int main(void) {

char       buf[80];

time_t disp_time;
struct tm *timeinfo;
time (&disp_time);
timeinfo = localtime (&disp_time);
strftime(buf, sizeof(buf), "%a %Y-%m-%d %H:%M:%S %Z", timeinfo);
printf("%s\n", buf);
return 0;

} This is a test from my program. Time is UTC. Need to subtract tz offset to get local time.

Scoured the internet looking for and explanation or an example. Nothing found.