struct timeval in C

/*

 * The timeval Structure,

 * strcut timval example in c

 * using timeval structure

 */

If you remember the select function arguments in socket,the last argument, timeout, points to a structure that must be initialized unless a NULL pointer is provided instead. Listing 11.3 shows the definition of the timeval structure.

/*

 * Listing 11.3: The Definition of the timeval Structure

 */

 struct timeval {

   long tv_sec;    /* seconds */

   long tv_usec;   /* microseconds */

};

To establish a timeout value of 1.75 seconds, you would code something like this:

Example

struct timeval tv;

tv.tv_sec = 1;

tv.tv_usec = 750000;

The example shows the establishing of a timeout of 1.75 seconds. This is done by setting up a timeout of one second plus 750,000 microseconds.

CAUTION

Note that the timeval structure values are modified by the select(2) call. The timeval structure should be re -initialized prior to each call to select(2), unless the program requires that the time remaining be used as the timeout.