C++ Converting a time string to seconds from the epoch

Question

I have a string with the following format:

2010-11-04T23:23:01Z

The Z indicates that the time is UTC.
I would rather store t

Answer 1

X/Open provides a global timezone variable which indicates the number of seconds that local time is behind UTC. You can use this to adjust the output of mktime():

#define _XOPEN_SOURCE
#include 
#include 

/* 2010-11-04T23:23:01Z */
time_t zulu_time(const char *time_str)
{
    struct tm tm = { 0 };

    if (!strptime(time_str, "%Y-%m-%dT%H:%M:%SZ", &tm))
        return (time_t)-1;

    return mktime(&tm) - timezone;
}