83Plus:Software:usb8x/Asm Interface/MSD/DOS openFile

Synopsis

Name: DOS_openFile

Minimum usb8x version: 0.10

Opens a file for reading or writing by populating a file handle containing important information.

Inputs

• HL points to ASCIIZ filename including path (ex. "/TESTDIR/TEST.TXT",0)
• DE points to a location to store the file handle (typically 27 bytes, size obtained by [[../MSDVersion|MSDVersion]])

Outputs

• File handle is populated and seek pointer is set to offset 0
• HL points to the file handle
• C set if problems

Destroys

• AF, BC, DE, HL

Notes

The filename is case-insensitive. There is also no "closing" a file. The file handle can be discarded when no more reading/writing is required. Example code to open "README.TXT" for reading/writing (storing file handle to statVars):

ld hl,sFilename
ld de,statVars
U_CALL DOS_openFile
jr c,openFileError
;HL points to file handle
...
openFileError:
...
sFilename: DB "/TESTDIR/README.TXT",0

See Also

• [[../DOS_fileSeek|DOS_fileSeek]] - Set seek pointer of file handle
• [[../DOS_fileRead|DOS_fileRead]] - Read bytes from a file
• [[../DOS_fileWrite|DOS_fileWrite]] - Write bytes to a file