C Programming/POSIX Reference/utime.h
int utime(const char *path, const struct utimbuf *times)
This function sets the access and modification times of the specified file.
The utime() function sets the access and modification times of the file named by the path argument.
Data types defined in the
utime.h header include:
time_t actimeaccess time
time_t modtimemodification time
The times are measured in seconds since the Epoch.