C program to demonstrate example of delay function. Dos.h delay function in C: Here, we will learn about the delay function of dos.h header file in C through a simple example/program. Delay function is used to hold the program's execution for given number of milliseconds, it is declared in dos.h header file. Delay(3, function -Executes function after 3 seconds.CODE end) What is Delay? I tried to find this but no results and i read about yielding script on roblox developer, it says: ' Yields. This is a yielding function. When called, it will pause the Lua thread that called the function until. Delay in C: delay function is used to suspend execution of a program for a particular time. Declaration: void delay (unsigned int); Here unsigned int is the number of milliseconds (remember 1 second = 1000 milliseconds). To use delay function in your program you should include the 'dos.h' header file which is not a part of standard C library. Dev-C is a free full-featured integrated development environment (IDE) distributed under the GNU General Public License for programming in C and C.It was originally developed by Colin Laplace and first released in 1998. It is written in Delphi. It is bundled with, and uses, the MinGW or TDM-GCC 64bit port of the GCC as its compiler.Dev-C can also be used in combination with Cygwin.