I am working on a function to format the input timestamp to the input format.
std::string 1stformat = "dd - MM - yyyy HH 'Hours' mm 'Minutes' ss 'Seconds' SSS 'Miliseconds –' a '– Time Zone: ' Z '-' zzzz";//will not print anything
std::string 2ndformat = "'This took about' h 'minutes and' s 'seconds.'";//will print out
After format
char date_string[100];
strftime(date_string, 50, format.c_str(), curr_tm);
My problem is that there will be sometimes the input format too long which made the buffer date_string not enough to content. I am just getting into C++ for the past 3 weeks so I don't have much ex about this.
A wrapper for strftime() that grows a buffer as needed until it's big enough to fit the desired time string:
#include <ctime>
#include <iostream>
#include <memory>
#include <string>
std::string safe_strftime(const char *fmt, const std::tm *t) {
std::size_t len = 10; // Adjust initial length as desired. Maybe based on the length of fmt?
auto buff = std::make_unique<char[]>(len);
while (std::strftime(buff.get(), len, fmt, t) == 0) {
len *= 2;
buff = std::make_unique<char[]>(len);
}
return std::string{buff.get()};
}
int main() {
std::time_t now;
std::time(&now);
std::cout << safe_strftime("The date is %Y-%m-%d", std::localtime(&now))
<< '\n';
return 0;
}