#ifndef HFIELD_H#define HFIELD_Hextern unsigned int hfield_skipname();extern int hfield_known();extern int hfield_valid();#define H_SENDER 1#define H_FROM 2#define H_REPLYTO 3#define H_TO 4#define H_CC 5#define H_BCC 6#define H_DATE 7#define H_MESSAGEID 8#define H_SUBJECT 9#define H_R_SENDER 10#define H_R_FROM 11#define H_R_REPLYTO 12#define H_R_TO 13#define H_R_CC 14#define H_R_BCC 15#define H_R_DATE 16#define H_R_MESSAGEID 17#define H_RETURNRECEIPTTO 18#define H_ERRORSTO 19#define H_APPARENTLYTO 20#define H_RECEIVED 21#define H_RETURNPATH 22#define H_DELIVEREDTO 23#define H_CONTENTLENGTH 24#define H_CONTENTTYPE 25#define H_CONTENTTRANSFERENCODING 26#define H_NOTICEREQUESTEDUPONDELIVERYTO 27#define H_MAILFOLLOWUPTO 28#define H_NUM 29#endif