Converting string containing localtime into UTC in C

Question

I have a string containing a local date/time and I need to convert it to a time_t value (in UTC) - I\'ve been trying this:

char* date = \"2009/09/01/00\";
st         


        

Answer 1

I think I've cracked it now, thanks to Andomar - this code does what I need and appears to work regardless of the current DST status (I changed the clock on my PC to check this):

#include 
#include 

time_t parseLocalDate(char* date){
    struct tm cal = {0, 0, 0, 0, 0, 0, 0, 0, -1, 0, NULL};
    strptime(date, "%Y/%m/%d/%H", &cal);
    return mktime(&cal);
}

int main(int argc, char *argv[]){
 // DST is effect, Local Time = GMT+1
    assert(1251759600 == parseLocalDate("2009/09/01/00")); // Mon, 31 Aug 2009 23:00:00 GMT
    assert(1254351600 == parseLocalDate("2009/10/01/00")); // Wed, 30 Sep 2009 23:00:00 GMT
 // DST not in effect, Local Time = GMT
    assert(1257033600 == parseLocalDate("2009/11/01/00")); // Sun, 01 Nov 2009 00:00:00 GMT
}