C++ Converting a Datetime String to Epoch Cleanly

问题:

Is there a C/C++/STL/Boost clean method to convert a date time string to epoch time (in seconds)?

yyyy:mm:dd hh:mm:ss 

回答1:

See: Date/time conversion: string representation to time_t

And: [Boost-users] [date_time] So how come there isn't a to_time_t helper func?

So, apparently something like this should work:

#include <boost/date_time/posix_time/posix_time.hpp> using namespace boost::posix_time;  std::string ts("2002-01-20 23:59:59"); ptime t(time_from_string(ts)); ptime start(gregorian::date(1970,1,1));  time_duration dur = t - start;  time_t epoch = dur.total_seconds();     

But I don't think it's much cleaner than Rob's suggestion: use sscanf to parse the data into a struct tm and then call mktime.

回答2:

On Windows platform you can do something like this if don't want to use Boost:

// parsing string SYSTEMTIME stime = { 0 }; sscanf(timeString, "%04d:%02d:%02d %02d:%02d:%02d",        &stime.wYear, &stime.wMonth,  &stime.wDay,        &stime.wHour, &stime.wMinute, &stime.wSecond);  // converting to utc file time FILETIME lftime, ftime; SystemTimeToFileTime(&stime, &lftime); LocalFileTimeToFileTime(&lftime, &ftime);  // calculating seconds elapsed since 01/01/1601 // you can write similiar code to get time elapsed from other date ULONGLONG elapsed = *(ULONGLONG*)&ftime / 10000000ull; 

If you prefer standard library, you can use struct tm and mktime() to do the same job.

回答3:

http://www.boost.org/doc/libs/1_39_0/doc/html/date_time.html Should do the trick.

文章来源: C++ Converting a Datetime String to Epoch Cleanly