how to convert datetime to unix timestamp in c?

Question

the scenario is: I get datetime in format \"YYYY-MM-DD HH:MM:SS\" with libexif. To minimize the saving cost, I wanna convert the datetime to unix timestamp or alike which on

Answer 1

What about sscanf?

struct tm tmVar;
char *strVar = "YYYY-MM-DD HH:MM:SS";
time_t timeVar;
if(sscanf(strVar, "%d-%d-%d %d:%d:%d", &tm.tm_year, /* the other fields */)==6)
    timeVar = mktime(&tmVar);
else
    // bad format