What is intptr_t,is it a type for integer or pointer?

Question

It's defined in /usr/include/stdint.h:

typedef long int                intptr_t;

is it supposed to be a type for integer or pointer?

Answer 1

It is a signed integer type that is big enough to hold a pointer.

Answer 2

It is a signed integer type that guaranteed to can hold a void* type.

And why there is also [u]intptr_t? Because:

Any valid pointer to void can be converted to intptr_t or uintptr_t and back with no change in value. The C Standard guarantees that a pointer to void may be converted to or from a pointer to any object type and back again and that the result must compare equal to the original pointer. Consequently, converting directly from a char * pointer to a uintptr_t is allowed on implementations that support the uintptr_t.