RstFLock
RstFLock Unlock a file (allow changes, deletion, renaming, etc.)
#include <Files.h> File Manager
Str255 fileName ; address of length-prefixed full or partial name
short vRefNum ; volume or working directory reference
returns Error Code; 0=no error
RstFLock locks a file; it undoes the effect of SetFLock. This allows
programs to delete, rename, or write data to it.
fileName is the address of a length-prefixed, pascal-style string containing
the name of the file to be unlocked. It may be a partial or full
pathname, depending upon the value of vRefNum .
vRefNum is the reference number of the volume or working directory that
contains the file or directory fileName. Use 0 to specify the default
volume.
Returns: an operating system Error Code. It will be one of:
noErr (0) No error
extFSErr (-58) External file system
fnfErr (-43) File not found
ioErr (-36) I/O error
nsvErr (-35) No such volume
vLckdErr (-46) Volume is locked
wPrErr (-44) Diskette is write-protected

Notes: This clears the file's "lock" flag (as found in the ioFlAttrib field of the
FileParam structure) and notifies the system of the change (Note: changing
this bit directly, e.g., via PBSetCatInfo, may not be noticed by the Finder
until the file's folder is closed and reopened or the system is restarted).
This does not affect currently-open access paths. Thus, if some other
process has opened the file, locking it will not prevent the other program
from continuing to modify it.
See SetFLock for related details. You can lock/unlock an entire volume
via PBSetVInfo or lock a selected portion of an open file via
PBLockRange. Use PBGetFInfo to see if a file is currently locked
(ioFlAttrib bit 1 is set).