Concatanate macro argument with another token

Question

I want to create function name inside macro depending on type defined by another macro. For example if I have defined the following macro:

#define TYPE int

my function name should look like this

int_allocate

I have tried this:

#define CREATE_NAME(VTYPE) VTYPE _allocate
#define FUNCTION_NAME CREATE_NAME(TYPE)
FUNCTION_NAME

and got the following line

int _allocate

as you can see there is one space between int and _allocate. I know how to concatenate these lines, it should be

#define CREATE_NAME(VTYPE) VTYPE ## _allocate

but in this case instead of getting int_allocate I get TYPE_allocate. When I pass int as argument I get correct result

#define FUNCTION_NAME CREATE_NAME(int)

but I need to pass macro as argument

How to solve this problem? Thanks in advance.