Problem with time() using g++

**Gary Labowitz** · Jul 22 '05, 10:16 AM

Re: Problem with time() using g++

"Mike Alexeev" <michael.alexee v@qwest.com> wrote in message
news:85062ee4.0 404270631.63ef8 eff@posting.goo gle.com...[color=blue]
> Hi all,
> I have come across very strange behavior of the return value of the
> time() function. Below is the program to illustrate the problem: The
> value of NOW somehow changes after the call to the ifstream
> constructor.
>
> #include <iostream>
> #include <fstream>
> #include <time.h>
>
> int main(int argc, char** argv)
> {
> if (argc != 2)
> {
> std::cout << "Usage: ctest filename" << std::endl;
> exit(-1);
> }
> time_t NOW = time(0);
> std::cout << "Start time before the call to ifstream(): NOW="
> << NOW << std::endl;
> std::ifstream infile(argv[1]);
> std::cout << "Start time after the call to ifstream(): NOW="
> << NOW << std::endl;
> infile.close();
> exit(0);
> }
>
> I tried this program with g++ 3.1.1 compiler on Solaris 5.8 and here
> is the output:
>[color=green]
> > g++ -o test test.cxx
> > test test.cxx[/color]
> Time before the call to ifstream(): NOW=1083075439
> Time after the call to ifstream(): NOW=27503[color=green]
> >[/color]
>
> Given the signature of the time() (time_t time(time_t* t)) I was not
> able to find any reasonable explanation how the call to the ifstream
> constructor could affect the local variable it does not know about[/color]
so[color=blue]
> any help would be greatly appreciated.
>
> By the way, I tried the same program with CC Sun Workshop 6.2 and it
> works fine.[color=green]
> > CC -o test test.cxx
> > test test.cxx[/color]
> Time before the call to ifstream(): NOW=1083075848
> Time after the call to ifstream(): NOW=1083075848[/color]

Works fine with gcc 3.2 on W2K.
Time to reinstall!
--
Gary

**Jeff Schwab** · Jul 22 '05, 10:17 AM

Re: Problem with time() using g++

Mike Alexeev wrote:[color=blue]
> Hi all,
> I have come across very strange behavior of the return value of the
> time() function. Below is the program to illustrate the problem: The
> value of NOW somehow changes after the call to the ifstream
> constructor.
>
> #include <iostream>
> #include <fstream>
> #include <time.h>
>
> int main(int argc, char** argv)
> {
> if (argc != 2)
> {
> std::cout << "Usage: ctest filename" << std::endl;
> exit(-1);
> }
> time_t NOW = time(0);
> std::cout << "Start time before the call to ifstream(): NOW="
> << NOW << std::endl;
> std::ifstream infile(argv[1]);
> std::cout << "Start time after the call to ifstream(): NOW="
> << NOW << std::endl;
> infile.close();
> exit(0);
> }
>
> I tried this program with g++ 3.1.1 compiler on Solaris 5.8 and here
> is the output:
>
>[color=green]
>>g++ -o test test.cxx
>>test test.cxx[/color]
>
> Time before the call to ifstream(): NOW=1083075439
> Time after the call to ifstream(): NOW=27503
>
>
> Given the signature of the time() (time_t time(time_t* t)) I was not
> able to find any reasonable explanation how the call to the ifstream
> constructor could affect the local variable it does not know about so
> any help would be greatly appreciated.
>
> By the way, I tried the same program with CC Sun Workshop 6.2 and it
> works fine.
>[color=green]
>>CC -o test test.cxx
>> test test.cxx[/color]
>
> Time before the call to ifstream(): NOW=1083075848
> Time after the call to ifstream(): NOW=1083075848[/color]

Try putting this after your #include's:

#undef NOW

Alternatively, don't use all-caps identifiers for anything but macros.

**Mike Alexeev** · Jul 22 '05, 10:19 AM

Re: Problem with time() using g++

Jeff Schwab <jeffplus@comca st.net> wrote in message news:<g9mdnTuZ6 9CwdxPd4p2dnA@c omcast.com>...[color=blue]
> Mike Alexeev wrote:[color=green]
> > Hi all,
> > I have come across very strange behavior of the return value of the
> > time() function. Below is the program to illustrate the problem: The
> > value of NOW somehow changes after the call to the ifstream
> > constructor.
> >
> > #include <iostream>
> > #include <fstream>
> > #include <time.h>
> >
> > int main(int argc, char** argv)
> > {
> > if (argc != 2)
> > {
> > std::cout << "Usage: ctest filename" << std::endl;
> > exit(-1);
> > }
> > time_t NOW = time(0);
> > std::cout << "Start time before the call to ifstream(): NOW="
> > << NOW << std::endl;
> > std::ifstream infile(argv[1]);
> > std::cout << "Start time after the call to ifstream(): NOW="
> > << NOW << std::endl;
> > infile.close();
> > exit(0);
> > }
> >
> > I tried this program with g++ 3.1.1 compiler on Solaris 5.8 and here
> > is the output:
> >
> >[color=darkred]
> >>g++ -o test test.cxx
> >>test test.cxx[/color]
> >
> > Time before the call to ifstream(): NOW=1083075439
> > Time after the call to ifstream(): NOW=27503
> >
> >
> > Given the signature of the time() (time_t time(time_t* t)) I was not
> > able to find any reasonable explanation how the call to the ifstream
> > constructor could affect the local variable it does not know about so
> > any help would be greatly appreciated.
> >
> > By the way, I tried the same program with CC Sun Workshop 6.2 and it
> > works fine.
> >[color=darkred]
> >>CC -o test test.cxx
> >> test test.cxx[/color]
> >
> > Time before the call to ifstream(): NOW=1083075848
> > Time after the call to ifstream(): NOW=1083075848[/color]
>
> Try putting this after your #include's:
>
> #undef NOW
>
> Alternatively, don't use all-caps identifiers for anything but macros.[/color]

The name does not matter. I tried it with different ones with the same result.

Problem with time() using g++

Problem with time() using g++

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