Are pointers considered a method of calling by reference in C?

Question

In my University\'s C programming class, the professor and subsequent book written by her uses the term call or pass by reference when referring to poin

Answer 1

In languages which support pass-by-reference, there exists a means by which a function can be given something that can be used to identify a variable know to the caller until the called function returns, but which can only be stored in places that won't exist after that. Consequently, the caller can know that anything that will be done with a variable as a result of passing some function a reference to it will have been done by the time the function returns.

Compare the C and C# programs:

// C               // C#
int x=0;           int x=0;
foo(&x);           foo(ref x);
x++;               x++;
bar();             bar();
x++;               x++;
boz(x);            boz(x);

The C compiler has no way of knowing whether "bar" might change x, because foo() received an unrestricted pointer to it. By contrast, the C# compiler knows that bar() can't possibly change x, since foo() only receives a temporary reference (called a "byref" in .NET terminology) to it and there is no way for any copy of that byref to survive past the point where foo() returns.

Passing pointers to things allows code to do the same things that can be done with pass-by-ref semantics, but pass-by-ref semantics make it possible for code to offer stronger guarantees about things it won't do.