[Dev-C++] The delay() function

[VINAY H. <wri...@gm...>]

I'm not able to use the delay() function in my programs.I tried
including the preprocessor directive "dos.h".Do tell me if i need to
use any other preprocessor directive.I've posted the errors which i
get when i try to compile for your reference.
1-->C:\Dev-Cpp\bin\duration.cpp [Warning] In function `int main()':
2-->24 C:\Dev-Cpp\bin\duration.cpp `delay' undeclared (first use this function).
3-->24 C:\Dev-Cpp\bin\duration.cpp (Each undeclared identifier is
reported only) .
and also i would request you to explain me the "compile delay" option
which is given in the compiler options,is this related to my first
part of the question? If yes how?