x86 Assembly Heap Memory Allocation -

i trying run code written professor. unfortunately, when compile , run code, results:

include irvine32.inc .data  array_size = 1000 fill_val equ 0ffh   hheap   handle ?                        ;handle process heap  parray  dword ?                         ;pointer block of memory  newheap dword ?                         ;handle new heap  str1 byte "heap size is: ",0  getprocessheap proto  .code  main proc       invoke getprocessheap                   ;get handle prog's heap      .if eax = null                          ;if failed, display message     call writewindowsmsg     jmp quit      .else      mov hheap, eax                          ;success      .endif       call allocate_array      jnc arrayok                             ;failed (cf = 1)?     call writewindowsmsg     call crlf      jmp quit   arrayok:     call fill_array      call display_array      call crlf       ;free array      invoke heapfree, hheap, 0, parray   quit:      exit  main endp   ;------------------------------------------------------- allocate_array proc uses eax  ; ;dynamically allocates space array  ;receives: eax = handle program heap  ;returns: cf = 0 if memory allocation succeeds  ;------------------------------------------------------- invoke heapalloc, hheap, heap_zero_memory, array_size       .if eax == null         stc                         ;return cf = 1      .else          mov parray, eax             ;save pointer          clc                         ;return cf = 0     .endif       ret  allocate_array endp   ;-------------------------------------------------------- fill_array proc uses ecx edx esi  ; ;fills array positions single character  ;receives: nothing  ;returns: nothing  ;---------------------------------------------------------      mov ecx, array_size             ;loop counter      mov esi, parray                 ;point array   l1: mov byte ptr [esi], fill_val    ;fill each byte      inc esi                         ;next location      loop l1       ret  fill_array endp  ;--------------------------------------------------------- display_array proc uses eax ebx ecx esi   ; displays array  ; receives: nothing  ; returns: nothing   mov ecx, array_size     ;loop counter  mov esi, parray         ;point array   l1: mov al, [esi]       ;get byte      mov ebx, type byte      call writehexb      ;display      inc esi             ;next location      loop l1       ret  display_array endp  end main  

the following results:

bobnew.asm(41) : error a2006: undefined symbol : heapfree bobnew.asm(56) : error a2006: undefined symbol : heapalloc bobnew.asm(22) : error a2006: undefined symbol : writewindowsmsg bobnew.asm(30) : error a2006: undefined symbol : writewindowsmsg bobnew.asm(97) : error a2006: undefined symbol : writehexb 

can explain why. thanks. curious how heap memory allocation , how invoke , handlers , proto works together. understand heap memory set aside dynamic memory allocation , unlike stack, there's no set pattern how memory allocated or deallocated. can allocate , deallocate @ time randomly , free allocated memory time. also, unlike stack, heap memory must manually destroyed prevent memory.

how building executable?

in order use functions heapfree, need link kernel32. how can vary linker you're using. in masm may mean writing

include     \masm32\include\kernel32.inc includelib  \masm32\lib\kernel32.lib