The structure **```timespec```** is defined in the ```time.h``` library of C and is used to store data such as time-elapsed. It allows the user to store time in seconds and nanoseconds. 

The ```time.h``` library must be included in the program to use the ```timespec``` structure as we see here:

```C
#include <time.h>
```




# Declaration
```C
struct timespec {
    time_t tv_sec;
    long tv_nsec;
};
```
The ```timespec``` struct contains two member variables:

* **`tv_sec`** -- The variable of the time_t type made to store time in seconds.
* **`tv_nsec`** -- The variable of the long type used to store time in nanoseconds.

Both variables are public by default as ```timespec``` is a struct.

# Example

The code snippet below demonstrates how we may use member variables of the ```timespec``` structure to store time-elapsed in seconds and nanoseconds. 

We declare a struct of type ```timespec```and set the values of tv_sec and tv_sec to 56 and 100, respectively. Each member variable is accessed using the dot notation, and we may reset its value at any point in time in the code. The ```printf``` function is used to print the values set by the programmer, which takes in a format string and pointers to variables in which the data that needs to be printed is stored.

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

int main()
{

  struct timespec time;
  time.tv_sec = 56;
  time.tv_nsec = 100;
  printf("%lld.%.9ld seconds have elapsed!", (long long) time.tv_sec, time.tv_nsec);
  printf("\nOR \n%d seconds and %ld nanoseconds have elapsed!", time.tv_sec, time.tv_nsec);
  return 0;
}

What is timespec in C?

The `timespec` struct from `time.h` in C stores time in seconds (`tv_sec`) and nanoseconds (`tv_nsec`).