segmentation fault (core dumped) error when using time function

Question

Hello i am new to Linux and c programming so this might be stupid question but i couldn't find an answer.

I am writing a home work and they want me to print the execution time at the end of program using time() function, so when i used the function in my program i got the message segmentation fault (core dumped) and when i remove it the program works agine. Then i created a test file in the code below :

#include <stdio.h>

int main()
{
    time();
    return 0;
}

And i got the same error message.

Also tried :

#include <stdio.h>

int main()
{
    time(NULL);
    return 0;
}

And

#include <stdio.h>
#include <time.h>

int main()
{
    time_t t;

    time(&t);
    return 0;
}

And got the same error.

so what i am doing wrong ?

Thanks

Answer 1

In your first two examples, you forget to include time.h. That is the cause of the segmentation fault in those examples. If you're using gcc, try compiling with -Wall (which turns on all warnings). You should get a warning indicating an implicit declaration of function "time" - in other words, that you've forgotten to include time.h.

Your final example, however, works fine for me. If you keep getting a segmentation fault, however, try debugging with gdb.

Answer 2

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void)
{
  time_t now;
  time(&now);

  printf("%s", ctime(&now));

  return EXIT_SUCCESS;
}