NWWriteEA(3nw)

NWWriteEA -- writes data to Extended Attribute

Synopsis

   #include <nwnamspc.h> 
   #include <nwea.h> 
   or 
   #include <nwcalls.h> 
    
   NWCCODE N_API NWWriteEA 
     (NW_EA_HANDLE N_FAR     EAHandle, 
      nuint32                 totalWriteSize, 
      nuint32                 bufferSize, 
      pnuint8                 buffer, 
      pnuint32                amountWritten);

Description

The parameters are as follows:

EAHandle: (IN/OUT) Points to NW_EA_HANDLE returned by either NWGetEAHandleStruct, NWFindFirstEA, NWFindNextEA, or NWOpenEA.
totalWriteSize: (IN) Specifies the size of the total Write.
bufferSize: (IN) Specifies the size of the buffer.
buffer: (IN) Points to a data buffer.
amountWritten: (OUT) Points to the amount of data written by NWWriteEA (not cumulative across multiple calls).

Return values

0x0000: SUCCESSFUL; valid data remains in the EA
0x0001: SUCCESSFUL; valid data remains in the buffer, not the EA
0x8901: ERR_INSUFFICIENT_SPACE
0x898C: NO_MODIFY_PRIVILEGES
0x899C: INVALID_PATH
0x89C8: MISSING_EA_KEY
0x89C9: EA_NOT_FOUND
0x89CB: EA_NO_KEY_NO_DATA
0x89CE: EA_BAD_DIR_NUM
0x89CF: INVALID_EA_HANDLE
0x89D0: EA_POSITION_OUT_OF_RANGE
0x89D1: EA_ACCESS_DENIED
0x89D2: DATA_PAGE_ODD_SIZE
0x89D3: EA_VOLUME_NOT_MOUNTED
0x89D4: BAD_PAGE_BOUNDARY
0x89FF: HARDWARE_FAILURE

Notices

If the EA does not exist, NWWriteEA attempts to create it.

NWWriteEA returns 0x0000 when there is more data in the EA and NWWriteEA needs to be called again. NWWriteEA returns 0x0001 when there is valid data in the buffer but none left in the EA.

NWReadEA and NWWriteEA can perform multiple actions, such as opening or creating an EA and then performing the appropriate function. To properly end NWWriteEA, NWCloseEA must be called after the last Read, Write, and/or Find EA function.

Extended Attribute values should always be read or written completely. Extended Attributes are not treated like files when transferring. Therefore, partial Reads or Writes are not allowed.

CAUTION: If an Extended Attribute is not read or written completely, data past the end of the last Read or Write may be lost!

Before calling NWWriteEA, an application must properly initialize NW_EA_HANDLE to access the EA database. An application can initialize NW_EA_HANDLE by calling NWFindFirstEA, NWFindNextEA, NWGetEAHandleStruct, or NWOpenEA. NW_EA_HANDLE is for internal use only; applications must not manipulate it in any way.

For Writes, bufferSize should be at least 512 bytes. If bufferSize is less than totalWriteSize, it must be a multiple of 512.

NWWriteEA writes up to the bufferSize number of EA information bytes or until the end of the EA data, whichever comes first. If the data to be written is larger than the buffer size, NWWriteEA must be called multiple times to write all the data to the EA.

An application should complete the entire Write before closing the EA.

Services

Extended Attribute

NCP calls

0x2222 86 02 Write Extended Attribute

 
 0x2222   86   02   Write Extended Attribute

References

NWReadEA(3nw)