Hi,
is it possible in C to allocate dynamically a global variable??
Depends on your meaning. You can't suddenly decide for a global integer named 'bill' to start existing when you never declared one at compile-time. For that matter, any variable of any sort in C must be declared at compile-time. But you can make a global pointer and allocate memory for it to point to later.
ok, can i for example declare a pointer to integer and allocate memory to it inside any function? how can i deallocate memory?
Yes you can allocate memory inside any function and deallocate it with free...though sample code would help understand what you are trying to do.