How to access the fields of a timeval structure

Question

I'm trying to print the values in a struct timeval variable as follows:

int main()  
{  

    struct timeval *cur;  
    do_gettimeofday(cur);  
    printf("Here is the time of day: %ld %ld", cur.tv_sec, cur.tv_usec);  

    return 0;  
}  

I keep getting this error:

request for member 'tv_sec' in something not a structure or union.  
request for member 'tv_usec' in something not a structure or union.

How can I fix this?

Answer 1

Because cur is a pointer. Use

struct timeval cur;
do_gettimeofday(&cur);

In Linux, do_gettimeofday() requires that the user pre-allocate the space. Do NOT just pass a pointer that is not pointing to anything! You could use malloc(), but your best bet is just to pass the address of something on the stack.