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Sender: cygwin-developers-owner AT sources DOT redhat DOT com
Date: Wed, 28 Feb 2001 13:42:05 +0100 (MET)
Message-Id: <200102281242.NAA01032@burner.fokus.gmd.de>
From: schilling AT fokus DOT gmd DOT de
To: cygwin-developers AT cygwin DOT com
Subject: fcntl(f, F_SETLK, &fl) problem on Cygwin 1.1.8(0.34/3/2)

It seems that a write lock on a file hold by a process
inhibits read access from the same process:

This piece of code in my editor (ved) 

        struct flock fl; 
        int     ret; 
 
        fl.l_whence = 0; 
        fl.l_start = 0; 
        fl.l_len = 0; 
        fl.l_type = 0; 
 
        fl.l_type |= F_WRLCK; 
         
        ret = fcntl(f, F_SETLK, &fl); 
        return (ret); 

Causes the problem:

 305  533760 [main] ved 1966225 _open: 4 = open (limit.c, 0x2)^M 
  457  534217 [main] ved 1966225 _fcntl: 0 = fcntl (4, 8, 0x255DC0C)^M 
  352  534569 [main] ved 1966225 _open: open (limit.c, 0x10000)^M 
  327  534896 [main] ved 1966225 dtable::build_fhandler: some disk file - cb 56, fd 5, fh 0x14590B28^M 
 1081  535977 [main] ved 1966225 fhandler_disk_file::open: (limit.c, 0x10000)^M 
  497  536474 [main] ved 1966225 mount_info::conv_to_win32_path: conv_to_win32_path (limit.c)^M 
  302  536776 [main] ved 1966225 normalize_posix_path: src limit.c^M 

looks OK, but later...

  378  543169 [main] ved 1966225 _open: 5 = open (limit.c, 0x10000)^M 
  335  543504 [main] ved 1966225 fhandler_base::fcntl: GETFL: 65536^M 
  279  543783 [main] ved 1966225 _fcntl: 65536 = fcntl (5, 3, 0x0)^M 
  282  544065 [main] ved 1966225 _cygwin_istext_for_stdio: _cygwin_istext_for_stdio (5)^M 
  266  544331 [main] ved 1966225 _cygwin_istext_for_stdio:  _cifs: get_*_binary^M 
  271  544602 [main] ved 1966225 setmode_helper: setmode: file was raw now raw^M 
  259  544861 [main] ved 1966225 setmode: setmode (5, binary) returns binary^M 
  315  545176 [main] ved 1966225 _cygwin_istext_for_stdio: _cygwin_istext_for_stdio (5)^M 
  269  545445 [main] ved 1966225 _cygwin_istext_for_stdio:  _cifs: get_*_binary^M 
  330  545775 [main] ved 1966225 _read: read (5, 0x255DC9C, 8192) blocking, sigcatchers 4^M 
  324  546099 [main] ved 1966225 _read: non-interruptible read^M 
  411  546510 [main] ved 1966225 fhandler_base::raw_read: ReadFile limit.c failed, Win32 error 33^M 
  314  546824 [main] ved 1966225 seterrno_from_win_error: /cygnus/netrel/src/cygwin-1.1.8-2/winsup/cygwin/fhandler.cc:239 errno 33^M 
  266  547090 [main] ved 1966225 geterrno_from_win_error: windows error 33 == errno 13^M 
  271  547361 [main] ved 1966225 _read: -1 = read (5<limit.c>, 0x255DC9C, 8192), bin 4096, errno 13^M 


Jörg

 EMail:joerg AT schily DOT isdn DOT cs DOT tu-berlin DOT de (home) Jörg Schilling D-13353 Berlin
       js AT cs DOT tu-berlin DOT de		(uni)  If you don't have iso-8859-1
       schilling AT fokus DOT gmd DOT de		(work) chars I am J"org Schilling
 URL:  http://www.fokus.gmd.de/usr/schilling   ftp://ftp.fokus.gmd.de/pub/unix