why can't i initialize a variable (i.e. int num=1) in c firmware, but it is ok to declare a variable (cont. )

Question

(i.e. int num;) then assign it a value later in a function? when i say "can't" i mean i get memory errors during compile time.

i am learning how to develop firmware on an embedded platform, i know it has to do with memory, but i don't know the details. if anyone can give me an overview of this problem and why it occurs, i would appreciate it.

thanks!

i am using keil compiler 6.03

Answer 1

thats just the way it works with embedded micro's and Keil. when you declare a variable, all the compiler is doing is assigning memory space for it. you then have to initialize it. Its really just the way the compiler works. it "could" initialize it when you declare it, but it would have to add the code to do that, and in the embedded world, you really dont want the compiler adding code because it might not add it where you want it (just my opinion, and experience).

Answer 2

An ansi compiler will allow you to do that. Which compiler are you using?

Answer 3

it is compiler dependent which compiler are you using