What does &PGRDShadow do in C programming ?

[Maya]

C again

Hi, i'm learning to programming in C and i've found this term in one program: &PGRDShadow , and i don't know exactly what it does, is some kind of register or something??? can some body help me?

Thanks

The complete instrucction of the program is :

BitWrPortI (PGDR,&PGDRShadow,Led1=led1?0:1,DS1)

 

[eltonjohn]

Re: C again

PGRDShadow is a variable declared somewhere
and &PGRDShadow is the address of such variable

When you call the function BitWrPortI (PGDR,PGDRShadow,Led1=led1?0:1,DS1) <-- without the & operator
then a new copy of the original PGDRShadow i created by the compiler
so the original is never changed .. this is called passing a parameter by value
In order to modify the original variable the REFERENCE has to be passed it means the address .. This is possible with the operator & !
so this is done in BitWrPortI (PGDR,&PGDRShadow,Led1=led1?0:1,DS1)

 

[echo47]

C again

Welcome to C!
As you learn, you will have many more questions. Here is an excellent FAQ:
https://www.eskimo.com/~scs/C-faq/top.html

 

[amer]

Re: C again

hi

refer Dietel & Dietel ..its a bible for C,C++.

each and every program with all error making possibilities r explained in this book.
if u really want to master C then u must read this book.

all the best
god bless U