Error Compiling C Code with Time and Date Functions.

Carl Flippin carlf at
Wed Dec 10 01:06:12 UTC 2008

On Tue, Dec 09, 2008 at 03:32:35PM -0600, Martin McCormick wrote:
> 	I portedd some code I had written in FreeBSD unix over to
> a new ubuntu-server system only to discover that none of the
> time and date functions compile in Linux but do so under
> FreeBSD. When referencing members of the structure timeptr such as
> (timeptr->tm_year - 100), (timeptr->tm_mon) + 1,     timeptr->tm_mday);
> 	compilation finds an error every time. The following
> fragment will produce the error:
>     struct tm *timeptr;
>     time_t elapsed_seconds; /*since midnight 1/1/70*/
>     time(&elapsed_seconds);
>     timeptr = localtime(&elapsed_seconds); /*fill structure*/
> sprintf(newalarm,"alarms%02d%02d%02d", (timeptr->tm_year - 100), (timeptr->tm_mon) + 1,     timeptr->tm_mday);


> #include <sys/time.h>

Your problem seems to be here. On my machine at lease, time.h is not
in /usr/include/sys. It's in /usr/include. The struct you are making a
pointer to above is not defined in sys/time.h. You need:

#include <time.h>

I do see the struct defined there. It is a part of libc6-dev.

Carl Flippin         | An idealist is one who, on noticing that a
carlf at  | rose smells better than a cabbage, concludes | that it will also make a better soup.
_____________________|      -- H. L. Mencken
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