Locks part or all of any file
HB_FLOCK( <nHandle>, <nOffset>, <nBytes> [, <nType ] ) --> <lSuccess>
<nHandle> Dos file handle
set> Offset of the first byte of the region to be locked.
<nBytes> Number of bytes to be locked.
e> The type (read or write) of lock requested.
<lSuccess> .T. if the lock was obtained, else .F.
This function attempts to lock a region of the file whose file handle is <nHandle>. This is a low level file function. To lock Harbour data files use either the FLOCK() or RLOCK() function.
The value of <nHandle> is obtained from either a call to the FOPEN() or the FCREATE() function.
<nOffset> is the offset (from the beginning of the file) to the first of the region to be locked. (Offsets from the current position nd of file are not currently supported.)
<nBytes> is the length of the region to be locked in bytes.
e> is the type of lock requested. There are two types of locks: sive write locks ( <nType> = 0x0000 ) – the default, and shared locks( <nType> = 0x0100 ). Additionally you can specify a ing version of this function (that is it won’t return until r an error has occurred or the lock has been obtained) by g Ox0200 to the above values.
refer to tfl.prg
Library is rtl
HB_FUNLOCK(), FOPEN(), FCREATE(), FERROR(), FCLOSE()