[fpc-pascal] (Unix) file locking
b.f.lundin at gmail.com
Tue Jun 21 07:41:24 CEST 2016
On 2016-06-21 00:37, Fabio Luis Girardi wrote:
> 2016-06-20 18:15 GMT-03:00 Björn Lundin <b.f.lundin at gmail.com
> <mailto:b.f.lundin at 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'
Apply, test or remove a POSIX lock on a section of an open file. The
file is specified by fd, a file descriptor open for writing, the action
by cmd, and the section consists of byte positions pos..pos+len-1 if
len is positive, and pos-len..pos-1 if len is negative, where pos is
the current file position, and if len is zero,the section extends from
the current file position to infinity, encompassing the present and
future end-of-file positions. In all cases, the section may extend
past current end-of-file.
It does not specify underlaying device - but you need an open file
> The best regards,
> Fabio Luis Girardi
> PascalSCADA Project
> fpc-pascal maillist - fpc-pascal at lists.freepascal.org
More information about the fpc-pascal