Nothing to do with Qt.

You want to retrieve a struct tm using one of the time-related function in glibc:
Get the time: http://www.delorie.com/gnu/docs/glibc/libc_433.html
Struct tm docs: http://www.delorie.com/gnu/docs/glibc/libc_435.html
An example: http://www.delorie.com/gnu/docs/glibc/libc_443.html