What is a makefile in iPhone development environment?

i have been developing iPhone apps for a few months now, i have gone through some examples of some iphone open source apps which have "makeFile" file in them. Just like cydia has got here Cydi开发者_运维问答a Source Code

i googled for it but couldnt get any satisfactory explanation of it. All explanations are somewhat complex.

Can somebody please explain me in simple language what this makefile is?

In Xcode, you select "Build" from the menu and it compiles your project. A Makefile does the same thing, except from the command line. A Makefile contains information about which files need to be rebuilt if you change a certain file.

See http://en.wikipedia.org/wiki/Makefile

Makefiles are nice because they work on a very wide variety of systems.

A make file is like an executable in windows. It has a preset list of commands to run in order to "make" your application work and it can manage your dependencies so you don't have to constantly respecify them. The alternative to a make file is running the application in a console.

The problem with running applications in a command line is that you may need to repeatedly specify all the project parameters whenever you want to run an application. Another downside to running an application from the command line is that you have to open the terminal/dos in order to run your application. Most end users of you application are not going to want to have to do this. Having a makefile makes starting up your application as easy as clicking on a makefile.

The main difference between a makefile and other files like .exe is they are platform independant and can be run in multiple operating systems.