int write_ipfix_message_header(ipfix_header *header, char **p_pos, char *p_end )
static int write_ipfix_message_header(ipfix_header *header, char **p_pos, char *p_end )
int write_ipfix_message_header(ipfix_header *header, char **p_pos, char *p_end ){	// check for available space	if (*p_pos + IPFIX_HEADER_LENGTH < p_end ) {		printf("Not enough memory allocated for header!\n");		return -1;	}	// initialize to zero.	memset(*p_pos, 0, IPFIX_HEADER_LENGTH);	// write the version information	write_unsigned16(p_pos, p_end, header->version);	// write the length information	write_unsigned16(p_pos, p_end, header->length);	// write the export time	write_unsigned32(p_pos, p_end, header->export_time);	// write the sequence_number	write_unsigned32(p_pos, p_end, header->sequence_number);	// write the source_id	write_unsigned32(p_pos, p_end, header->source_id);	return 0;}