What happens behind the scene when value is returned ?

[afesheir]

Dear everybody ..

I'm wondering what happens behind the scene when a function encounters return statement, and hence it starts to pass the value to the caller routine .. how does this process happen in details ?? Steps approach is very recommended to meet my understanding methodology

Thanks everybody for help in advance

[manasij7479]

what happens behind the scene ...

010111010110100000110111000101110101
010101011000000010111111111111100001
010111010110100110111000101110101010
010111010110100000110111000101110101
010111010110100000110000101110101010


Seriously..STFW
C Function Call Conventions, UMBC CMSC 313, Spring 2002

btw.. Welcome
(I'm sure Adak will post his signature welcome message soon ! )

[afesheir]

sorry Sir ?

[manasij7479]

sorry Sir ?

Did you follow the above link (or do a Web Search) ?

[CommonTater]

Dear everybody ..

I'm wondering what happens behind the scene when a function encounters return statement, and hence it starts to pass the value to the caller routine .. how does this process happen in details ?? Steps approach is very recommended to meet my understanding methodology

Thanks everybody for help in advance

Read the link Manasij provided for you...

In a nutshell...

The return value is placed in a CPU register
Local variables are destroyed
The program's stack is restored to it's "condition on entry"
The return address is taken from the stack
and, finally, the CPU jumps to the return address.

[afesheir]

Thanks guys .. this was very helpful ..

It's a pleasure to add the following:

x86 - What is stack frame in assembly? - Stack Overflow
Stack Frame

[KCfromNC]

Keep in mind that just because there's one way to do it doesn't mean that there aren't other ways depending on the CPU, OS, or compiler you're using. And the details will also differ if you return, for example, a large structure. And optimizations can combine, reorder or eliminate various steps.