iPhone app launch time, lifecycle question

Question

I\'m trying come up with a method to determine how long after the user taps the app icon it takes for the app to be ready for user input.

As far as I know, the first

Answer 1

Several things happen before main is called:

• address space is allocated (for stack, executable, ...)
• the executable is loaded
• process is linked to dyld (the dynamic linker)
• load commands in the mach header are performed (frameworks and libraries loaded)
• more pages get allocated for static storage of libraries
• dyld performs symbol resolving
• initializations of libraries and the executable are performed

This should only name a few of the things which happen before main gets called. You can put code in one of the initialization functions to be able to do something a little before main but don’t expect this to reduce the delay between tap and your code a lot.

You can declare a C function to be called before main like this:

void __attribute__ ((constructor)) my_init(void);

If you need to do Objective-C things, you can implement +initialize in one of your classes.