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You can use the type qualifiers const, restrict, and
volatile with array parameters; for example:
void
clobber4 (volatile int array[20])
…
denotes that array is equivalent to a pointer to a volatile
int. Alternatively:
void
clobber4 (int array[const 20])
…
makes the array parameter equivalent to a constant pointer to an
int. If we want the clobber4 function to succeed, it
would not make sense to write
void
clobber4 (const int array[20])
…
as this would tell the compiler that the parameter should point to an
array of constant int values, and then we would not be able to
store zeros in them.
In a function with multiple array parameters, you can use restrict
to tell the compiler that each array parameter passed in will be distinct:
void
foo (int array1[restrict 10], int array2[restrict 10])
…
Using restrict promises the compiler that callers will
not pass in the same array for more than one restrict array
parameter. Knowing this enables the compiler to perform better code
optimization. This is the same effect as using restrict
pointers (see restrict-Qualified Pointers), but makes it clear when reading
the code that an array of a specific size is expected.