cctz::parse error

[urykhy]

i'm trying to use cctz::parse but it seems have a problem with some formats:

    std::cout << "scanTime : " << scanTime("1970 02 02","%Y %m %d") << std::endl;
    std::cout << "scanTime : " << scanTime("19700202","%Y%m%d") << std::endl;

first line produce 2764800.
second - error.

full code:

#include <iostream>
#include <cctz/civil_time.h>
#include <cctz/time_zone.h>
#include <chrono>
using SC = std::chrono::system_clock;
time_t scanTime(const char* str, const char* format)
{
    std::chrono::system_clock::time_point tp;
    if (!cctz::parse(format, str, cctz::utc_time_zone(), &tp))
        return 0;
    return SC::to_time_t(tp);
}
int main(void)
{
    std::cout << "scanTime : " << scanTime("1970 02 02","%Y %m %d") << std::endl;
    std::cout << "scanTime : " << scanTime("19700202","%Y%m%d") << std::endl;
    return 0;
}

[devbww]

In the string "19700202" there is a year, 19700202, and then no month or day, so the parse fails. There is no backtracking on failed matches looking for alternatives.

If you want to limit yourself to 4-digit years, use the %E4Y format specifier.