For CPP

 /* Contents of file wcxhead.h */
 /* It contains definitions of error codes, flags and callbacks */
 
 /* Error codes returned to calling application */
 #define E_END_ARCHIVE     10            /* No more files in archive */
 #define E_NO_MEMORY       11            /* Not enough memory */
 #define E_BAD_DATA        12            /* Data is bad */
 #define E_BAD_ARCHIVE     13            /* CRC error in archive data */
 #define E_UNKNOWN_FORMAT  14            /* Archive format unknown */
 
 #define E_EOPEN           15            /* Cannot open existing file */
 #define E_ECREATE         16            /* Cannot create file */
 #define E_ECLOSE          17            /* Error closing file */
 #define E_EREAD           18            /* Error reading from file */
 #define E_EWRITE          19            /* Error writing to file */
 #define E_SMALL_BUF       20            /* Buffer too small */
 #define E_EABORTED        21            /* Function aborted by user */
 
 #define E_NO_FILES        22            /* No files found */
 #define E_TOO_MANY_FILES  23            /* Too many files to pack */
 #define E_NOT_SUPPORTED   24            /* Function not supported */
 
 /* flags for unpacking */
 #define PK_OM_LIST          0
 #define PK_OM_EXTRACT       1
 
 /* flags for ProcessFile */
 #define PK_SKIP             0            /* Skip this file */
 #define PK_TEST             1            /* Test file integrity */
 #define PK_EXTRACT          2            /* Extract to disk */
 
 /* Flags passed through ChangeVolProc */
 #define PK_VOL_ASK          0            /* Ask user for location of next volume */
 #define PK_VOL_NOTIFY       1            /* Notify app that next volume will be unpacked */
 
 /* Flags for packing */
 
 /* For PackFiles */
 #define PK_PACK_MOVE_FILES  1    /* Delete original after packing        */
 #define PK_PACK_SAVE_PATHS  2    /* Save path names of files             */
 
 /* Returned by GetPackCaps */
 #define PK_CAPS_NEW         1    /* Can create new archives              */
 
 #define PK_CAPS_MODIFY      2    /* Can modify exisiting archives        */
 #define PK_CAPS_MULTIPLE    4    /* Archive can contain multiple files   */
 #define PK_CAPS_DELETE      8    /* Can delete files                     */
 #define PK_CAPS_OPTIONS    16    /* Has options dialog                   */
 #define PK_CAPS_MEMPACK    32    /* Supports packing in memory           */
 #define PK_CAPS_BY_CONTENT 64    /* Detect archive type by content       */
 #define PK_CAPS_SEARCHTEXT 128   /* Allow searching for text in archives */
 
                                  /* created with this plugin}            */
 #define PK_CAPS_HIDE       256   /* Show as normal files (hide packer    */
                                  /* icon), open with Ctrl+PgDn, not Enter*/
 
 /* Flags for packing in memory */
 #define MEM_OPTIONS_WANTHEADERS 1  /* Return archive headers with packed data */
 
 {Errors returned by PackToMem}
 #define MEMPACK_OK          0    /* Function call finished OK, but there is more data */
 
 #define MEMPACK_DONE        1    /* Function call finished OK, there is no more data  */
 
 
 typedef struct {
     char ArcName[260];
     char FileName[260];
     int Flags;
     int PackSize;
     int UnpSize;
     int HostOS;
     int FileCRC;
     int FileTime;
     int UnpVer;
     int Method;
     int FileAttr;
     char* CmtBuf;
     int CmtBufSize;
     int CmtSize;
     int CmtState;
   } tHeaderData;
 
 typedef struct {
     char* ArcName;
     int OpenMode;
     int OpenResult;
     char* CmtBuf;
     int CmtBufSize;
     int CmtSize;
     int CmtState;
   } tOpenArchiveData;
 
 typedef struct {
 
 int size;
 	DWORD PluginInterfaceVersionLow;
 	DWORD PluginInterfaceVersionHi;
 	char DefaultIniName[MAX_PATH];
 } PackDefaultParamStruct;
 
 /* Definition of callback functions called by the DLL
 
 Ask to swap disk for multi-volume archive */
 
 typedef int (__stdcall *tChangeVolProc)(char *ArcName,int Mode);
 
 /* Notify that data is processed - used for progress dialog */
 
 typedef int (__stdcall *tProcessDataProc)(char *FileName,int Size);

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