Почему функции это тип данного

#include <stdio.h>
 
int main () {
    const unsigned char *byte = (const unsigned char*)&main;
    char hex[3] = {0x00,0x00,0x00};
    for (unsigned int id = 0; ; ++id) {
        hex[0] = (byte[id] & 0xF0) >> 4;
        hex[1] = (byte[id] & 0x0F);
        hex[0] += '0';
        hex[1] += '0';
        if (hex[0] > '9') hex[0] += 'A'-'9'-1;
        if (hex[1] > '9') hex[1] += 'A'-'9'-1;
        if (id && id % 16 == 0) putc('\x0a',stdout);
        printf("%s\x20",hex);
        if (byte[id+1] == 0x5D) {
            if (byte[id+2] == 0xC3) {
                if (id+1 % 16 == 0) putc('\x0a',stdout);
                printf("5D\x20");
                if (id+2 % 16 == 0) putc('\x0a',stdout);
                printf("C3\x20");
                break;
            }
        }
    }
    return 0;
}

#include <windows.h>
#include <stdio.h>
 
LPCVOID GetBasePageAddress (LPCVOID addr) {
    MEMORY_BASIC_INFORMATION info;
    LPCVOID base = 0;
    while (true) {
        VirtualQuery(base,&info,sizeof(MEMORY_BASIC_INFORMATION));
        if ((ULONG_PTR)addr >= (ULONG_PTR)info.BaseAddress && (ULONG_PTR)addr < (ULONG_PTR)info.BaseAddress+(ULONG_PTR)info.RegionSize) {
            break;
        } else base = (LPCVOID)((ULONG_PTR)info.BaseAddress+(ULONG_PTR)info.RegionSize);
    }
    return base;
}
 
int main () {
    DWORD old;
    LPCVOID page = GetBasePageAddress((LPCVOID)&main);
    MEMORY_BASIC_INFORMATION info;
    VirtualQuery(page,&info,sizeof(MEMORY_BASIC_INFORMATION));
    VirtualProtect(info.BaseAddress,info.RegionSize,PAGE_EXECUTE_READWRITE,&old);
    *(unsigned char*)&main = 0xFF;
    printf("%x",*(unsigned char*)&main);
    VirtualProtect(info.BaseAddress,info.RegionSize,old,&old);
    return 0;
}