C++ fwrite dosnt write to text file , have no idea why

[umen]

i did this and changed it to be binary open like this:
pfFile = fdopen(iFileId, "rb");
pDesfFile = fdopen(iFileId2, "wb");

and changed to :
size_t f = fwrite (buffer , 1, lSize ,pDesfFile );

but still empty file :
here is my full tester file , maybe its something in my pc , mybe if someone can run it so it will be great.
here is the code:

#include <stdio.h>
#include <stdlib.h>
#include <io.h>
#include <fcntl.h>
#include <string>
#include <share.h>
#include <sys\stat.h>


int main () {
  std::string szSource = "H:\\cpp\\test1.txt";
  FILE* pfFile;
  int iFileId = _sopen(szSource.c_str(),_O_RDONLY, _SH_DENYNO, _S_IREAD);
  if (iFileId >= 0) 
     pfFile = fdopen(iFileId, "rb");
   //read file content to buffer 
   char * buffer;
   size_t result;
   long lSize;
   // obtain file size:
   fseek (pfFile , 0 , SEEK_END);
   lSize = ftell (pfFile);
   fseek(pfFile, 0, SEEK_SET);
 //   buffer = (char*) malloc (sizeof(char)*lSize);
   buffer = (char*) malloc (sizeof(char)*lSize);

   if (buffer == NULL)
   {
     
       return false;
   }

   // copy the file into the buffer:
   result = fread (buffer,lSize,1,pfFile);   
   std::string szdes = "H:\\cpp\\test_des.txt";
   FILE* pDesfFile;
   int iFileId2 = _sopen(szdes.c_str(),_O_CREAT,_SH_DENYNO,_S_IREAD | _S_IWRITE);
  if (iFileId2 >= 0) 
     pDesfFile = fdopen(iFileId2, "wb");
     
   size_t f = fwrite (buffer , 1, sizeof(buffer),pDesfFile );
   //size_t f = fwrite (buffer , 1, lSize ,pDesfFile );
   printf("Error code: %d\n",ferror(pDesfFile));

   fclose (pDesfFile);
   
  return 0;
}