Document *load(string fileName){
 
	char *buffer;
	FILE *pFile;
	long lSize;
	size_t result;
	string strBuff;
	errno_t err;
	Document *document = new Document();
 
	err = fopen_s ( &pFile, fileName.c_str() , "rb" );
	strBuff = "Can't read file \""+fileName+"\"!";
	if (err) {fputs (strBuff.c_str(), stderr); exit (1);}
	if (pFile==NULL) {fputs ("File error",stderr); exit (1);}
 
	// obtain file size:
	fseek (pFile , 0 , SEEK_END);
	lSize = ftell (pFile);
	rewind (pFile);
 
	// allocate memory to contain the whole file:
	buffer = (char*) malloc (sizeof(char)*(lSize+1));
	if (buffer == NULL) {fputs ("Memory error",stderr); exit (2);}
 
	// copy the file into the buffer:
	result = fread (buffer,1,lSize,pFile);
	if (result != lSize) {fputs ("Reading error",stderr); exit (3);}
	/* the whole file is now loaded in the memory buffer. */
 
	// Here occurs the error. File has been read, but buffer is clear, 
	// strBuff.assign crashes.
	strBuff.assign(buffer);
	free (buffer);
	// terminate
	fclose (pFile);
	return parse(strBuff, document);
}