Point to header data for this file
Function AddressDescription
DOS_REF_HEAD 010FPoint to header data for this file


Point at the header data for this file.

The header data area is 8 bytes long and may be used by the caller for any purpose whatsoever. It is available even if the file does not have a header; however, only files with a header and opened with write access will have the header data recorded on disk.

Note that +3 BASIC uses these 8 bytes (see the note under DOS OPEN which gives the details). If creating a file that will subsequently be LOADed within BASIC, then those bytes should be filled with the relevant values.

Entry Parameters

Register Content
B File number 0…15

Exit Parameters

If OK:
Carry true
A corrupt
IX = Address of header data
Carry false
A = Error code
IX corrupt
BC DE HL corrupt, all other registers preserved.
The original manual doesn't mention exactly what IX points to after this call.

The address in IX is the +3 BASIC Header structure which is 8 bytes long. (IX+0) is the file type, (IX+1) the file length and (IX+3) param 1.

Last modified November 24, 2021: Start of +3DOS documentation (253d8cc)