CryptExportKey cant retrieve valid key size

i call CryptExportKey to get size of key, for buffer allocation

when i allocate buffer and use it in CryptExportKey again to actually export key, i get error ERROR_MORE_DATA

i decided print size, it turned out to be 148 (suspiciously small, probably thats why i get ERROR_MORE_DATA from next call)

so can anyone tell me whats wrong here ?

CryptExportKey(hKey,NULL,PUBLICKEYBLOB,0,NULL,&PublicKeySize)

PS CryptoApi gave error 87, because it turned out that last param (pointer to output size dword) should be set zero while i was not doing this because msdn was silent about this,

and this crap took me a while (about 10 days) to figure out (damn am i stupid ?), msdn is not documenting everything, and error values are too ambiguous

PPS i already spent 3 weeks figuring out how to use cryptoapi, and googled every possible tutorial\example that you will probably link . . .

PPPS i will post "source code"

#include <Windows.h>
#include <WinCrypt.h>
#include "ErrorLog.h" // PPPPS this is printf wrapper
#include "memory.h"   // GlobalAlloc wrapper with error check 

DWORD Keys(){
	HCRYPTPROV hCryptProv;
	HCRYPTKEY hKey;

	DWORD PublicKeySize=0;
	PBYTE PublicKey;

	//acquire context
	if(!CryptAcquireContext(&hCryptProv,"MyContainer1",NULL,PROV_RSA_FULL,0)){
		error("CryptAcquireContext",GetLastError());
		
		if(!CryptAcquireContext(&hCryptProv,"MyContainer1",NULL,PROV_RSA_FULL,CRYPT_NEWKEYSET)){
			error("CryptAcquireContext",GetLastError());
			return 1;
		}
	}

	if(!CryptGenKey(hCryptProv,AT_KEYEXCHANGE,CRYPT_ARCHIVABLE,&hKey)){
			error("CryptGenKey",GetLastError());

			CryptReleaseContext(hCryptProv,0);

			return 1;
	}

	error("Key Generated",0);

	if(!CryptExportKey(hKey,NULL,PUBLICKEYBLOB,0,NULL,&PublicKeySize)){
			error("CryptExportKey SIZE",GetLastError());

			CryptReleaseContext(hCryptProv,0);
			CryptDestroyKey(hKey);

			return 1;
	}
	
	error("pkey size",PublicKeySize);

	
	PublicKey = (PBYTE)Alloc(PublicKeySize);
	if(!PublicKey){
		goto FAIL_PKEY_ALLOC;
	}

	PublicKeySize=0;
	if(!CryptExportKey(hKey,NULL,PUBLICKEYBLOB,0,PublicKey,&PublicKeySize)){
			error("CryptExportKey KEY",GetLastError());

			FAIL_PKEY_ALLOC:
			CryptReleaseContext(hCryptProv,0);
			CryptDestroyKey(hKey);
			
			return 1;
	}

       ///   ///   ///   under construction   ///   ///   /// 
	
	return 0;
}