I have a problem with file region locking under Linux.
First I start setup to create a file and writelock range 10..30
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program setup;
{$mode delphi}{$H+}
Uses cthreads, Classes, SysUtils, BaseUnix;
Const Fn = '/home/anthony/test_lock';
F_RDLCK = 0;
F_WRLCK = 1;
F_UNLCK = 2;
Var F, I : Integer;
Region : FLock;
Begin
If FileExists (Fn) Then DeleteFile (Fn);
F := FpOpen (Fn, O_RDWR Or O_CREAT, $1B6); // $1B6 = o666
For I := 0 To 255 Do FpWrite (F, I, 1);
With Region Do
Begin
l_type := F_WRLCK; l_whence := SEEK_SET;
l_start := 10; l_len := 20
End;
If FpFcntl (F, F_SETLK, Region) = -1 Then
WriteLn ('unable to apply writelock'); // <-- OK
Sleep (20000); // Sleep 20 Sec
FpClose (F);
End.
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Then within 20 seconds i start test to obtain a readlock on 80.
This fails. Why? What am I doing wrong?
--------------------------------------------------------------------------------------
program test;
{$mode delphi}{$H+}
Uses cthreads, Classes, SysUtils, BaseUnix;
Const Fn = '/home/anthony/test_lock';
F_RDLCK = 0;
F_WRLCK = 1;
F_UNLCK = 2;
Var F, I : Integer;
Region : FLock;
Begin
F := FpOpen (Fn, O_RDWR Or O_CREAT, $1B6); // $1B6 = o666
With Region Do
Begin
l_type := F_RDLCK; l_whence := SEEK_SET;
l_start := 80; l_len := 1
End;
If FpFcntl (F, F_SETLK, Region) = -1 Then
WriteLn ('unable to apply readlock on 80'); // <-- Error
FpClose (F);
End.
------------------------------------------------------------------------------------
Thanks
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