CODEWITHSUNDEEP
cdatetime
binish
binish

Reputation: 85

Time function not working in c

I used the following code segment to get the system time. But it results in a segmentation fault. Please help.

printf("Time : %s\n", System("time"));
return 0;

Upvotes: 0

Views: 2003

Answers (4)

Jens
Jens

Reputation: 72629

The system() function returns an exit status (an int), not a string. Calling system("time") prints the time to stdout. If that's what you want, just use

 system("time");

You get a segfault because the int 0, when interpreted as a pointer for printf's %s is a NULL pointer. Dereferencing NULL pointers is undefined behavior and a segmentation fault is one possibility for such undefined behavior.

Upvotes: 2

Harikrishnan
Harikrishnan

Reputation: 8065

Use the following code instead:

time_t t;
time(&t);
printf("%s", ctime(&t));

This will solve your problem.

Upvotes: 3

Sjoerd
Sjoerd

Reputation: 75588

The system() function returns an integer, while %s indicates that you want to print a string. The system function does not return the result of the time program, but the exit value.

Upvotes: 1

NPE
NPE

Reputation: 500207

I assume you mean system() rather than System().

You seem to expect that system() would return a string containing whatever the command has printed to the terminal. It does not do that. In fact, system() returns the exit code of the child process.

The easiest way to get the current time is by using the time() function:

NAME
       time - get time in seconds

SYNOPSIS
       #include <time.h>

       time_t time(time_t *t);

DESCRIPTION
       time()  returns  the  time  since  the  Epoch (00:00:00 UTC, January 1,
       1970), measured in seconds.

       If t is non-NULL, the return value is also stored in the memory pointed
       to by t.

Upvotes: 2

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