Björn Lundin wrote:
On 2016-06-21 00:37, Fabio Luis Girardi wrote:> > > 2016-06-20 18:15 GMT-03:00 Björn Lundin <b.f.lun...@gmail.com>
<mailto:b.f.lun...@gmail.com>>:> > > on Linux and AIX I use lockf.> then read() and write() from the os.>
However I lock the whole file, but the manpage says it is possible to> lock parts of it.> > > > This can be used to
lock character devices, like /dev/ttyUSB0?> > FPC fpFLock does the same than Posix.Lockf?
that I do not know.from 'man lockf'DESCRIPTIONApply, test or remove a POSIX
lock on a section of an open file. Thefile is specified by fd, a file
descriptor open for writing, the actionby cmd, and the section consists of byte
positions pos..pos+len-1 iflen is positive, and pos-len..pos-1 if len is
negative, where pos isthe current file position, and if len is zero,the section
extends fromthe current file position to infinity, encompassing the present
andfuture end-of-file positions. In all cases, the section may extendpast
current end-of-file.
It does not specify underlaying device - but you need an open filedescriptor
The interesting question is what functions that translates to in Pascal
(specifically, FPC). I suspect FpFcntl() and FpRead() etc. rather than
anything higher-level (e.g. streams).
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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