What does void pointer actually mean?

[Niu Xiao]

I saw a lot of codes like:

void foo(void* arg)
void bar(void** arg)
f((void*)p)

but what does void pointer mean in c? I just know it stands for generic
pointer.

thanks.

 

[Keith Thompson]

I saw a lot of codes like:

void foo(void* arg)
void bar(void** arg)
f((void*)p)

but what does void pointer mean in c? I just know it stands for
generic pointer.

Right, it's a generic pointer. I'm not sure what you're asking.

"void" is a special type, an incomplete type that cannot be completed.
You can't have an object of type void; a function that returns void
doesn't return a value.

Type "void*" is a pointer type that can point to any object. An
object of type void* can hold a value of any pointer-to-object type.
Any object type can be implicitly converted to void*, and vice versa.

 

[Jack Klein]

Right, it's a generic pointer. I'm not sure what you're asking.

"void" is a special type, an incomplete type that cannot be completed.
You can't have an object of type void; a function that returns void
doesn't return a value.

Type "void*" is a pointer type that can point to any object. An
object of type void* can hold a value of any pointer-to-object type.
Any object type can be implicitly converted to void*, and vice versa.

Of course you meant your last sentence above to read:

A pointer to any object type can be implicitly converted to void*, and
vice versa.

 

[Keith Thompson]

in comp.lang.c: [...]

Type "void*" is a pointer type that can point to any object. An
object of type void* can hold a value of any pointer-to-object type.
Any object type can be implicitly converted to void*, and vice versa.

Of course you meant your last sentence above to read:

A pointer to any object type can be implicitly converted to void*, and
vice versa.

Yes, thanks.

 

[Niu Xiao]

Right, it's a generic pointer. I'm not sure what you're asking.

"void" is a special type, an incomplete type that cannot be completed.
You can't have an object of type void; a function that returns void
doesn't return a value.

Type "void*" is a pointer type that can point to any object. An
object of type void* can hold a value of any pointer-to-object type.
Any object type can be implicitly converted to void*, and vice versa.

> Any object type can be implicitly converted to void*, and vice versa.

This sentence tells everything, thanks.

 

[Keith Thompson]

Keith Thompson wrote: [...]

Any object type can be implicitly converted to void*, and vice versa.

This sentence tells everything, thanks.

Except that it's wrong.

Any pointer-to-object type (not any object type) can be implicitly
converted to void*, and vice versa.