C wait function

To use delay function in your program you should include the dos. It is quite simple, and I believe it is portable. Of course, as Lightness Races in Orbit pointed out, you should not do this in order to be able to see an Hello World in your terminal, but there exist some good reason to use a wait func tion.

A humble request Our website is made possible by displaying online advertisements to our visitors. The clock() f unction returns a time value in clock ticks, which is based on the processor’s speed. The value returned is of the clock_t variable type. The following code demonstrates elapsed.

Ask Question Asked years, months ago. The wait system-call puts the process to sleep and waits for a child-process to end. The system call wait () is easy. This function blocks the calling process until one of its child processes exits or a signal is received.

For our purpose, we shall ignore signals. ID of the completed process. Some flags that indicate the completion. Delay in C : delay function is used to suspend execution of a program for a particular time.

You can set up a technique to allow time to tick away, for example: when showing a splash page (a notice or hint) for a game. In this post, we will see how to give a time delay in C code. Basic idea is to get current clock and add the required delay to that clock, till current clock is less then required clock run an empty loop. Here is implementation with a delay function.

Output: This article is contributed by Pratik Chhajer. You can use kill function to check if a process is alive. In the C language, sleep() accepts integers that represent the number of milliseconds the program should wait , which means you need to call sleep(500) to wait half a second. The clock() function returns a time value in clock ticks, which is based on the processor’s speed. Put your wait () function in a loop and wait for all the child processes.

The wait function will return -and errno will be equal to ECHILD if no more child processes are available. The delay is unpredictable - it will vary greatly depending on the computer and also the compiler, which may optimize it away to no delay at all, as other noted. The different sleep options leave a chance for the system to interrupt your process and let other processes perform some work (and you will be saving electricity as well). Note that the sleep family of functions will wait for a given period of time. And as the period gets shorter you will be spending more CPU in just calling the OS.

If sleep returns because the requested interval is over, it returns a value of zero. If it returns because of delivery of a signal, its return value is the remaining time in the sleep interval. All concurrent calls to wait member functions of this object shall use the same underlying mutex object (as returned by lck.mutex()). A callable object or function that takes no arguments and returns a value that can be evaluated as a bool. Wait for ready Waits for the shared state to be ready.

If the shared state is not yet ready (i.e., the provider has not yet set its value or exception), the function blocks the calling thread and waits until it is ready. The functions described in this section are used to wait for a child process to terminate or stop, and determine its status. A better way is to implement a software timer using a hardware resource like a timer or counter, or PWM, that can generate events at a known rate based on configuration and an input clock frequency. Use the _nop_ () function to insert a number of NO-OP instructions into your C code.

Figure out the amount of time it takes for a single NOP on your target and use as many as necessary. Create a function that starts a timer that generates an interrupt on overflow. The interrupt sets a flag that.

Sleep function delays program execution for a given number of seconds. Explanation : Delay function is used to suspend execution of a program for a particular time. How can I create a time delay ? How would one go about creating a delay between the executions of a function ? I have made a timer that counts down to zero from a number specified by the user.