system file watch crash

fsw = System.IO.FileSystemWatcher();
fsw.Path = 'C:\Users\wolfgang\Desktop';
fsw.Filter = 'NZDUSD1.csv';
fsw.EnableRaisingEvents = true;
listenerhandle = addlistener(fsw, 'Changed', @(~,~)importfcn(q,a));
%signature of importfcn is function importfcn(sender, eventargs)
%add a small delay in importfcn before reading the file as the event is raised
%to make sure that file modification is complete

When I run this file, .csv file gets imported every minute and then processed. Sometimes, the imported file is still processed and the next import is delayed. This leads to the delay of several files.

In the end my matlab crashed and I get an error message. How can I resolve this problem?

[Guillaume]

What is the error message?

[AA]

------------------------------------------------------------------------
    Unknown exception 0xe0434352 detected at Sun Jan 25 23:40:23 2015
------------------------------------------------------------------------

Configuration:
  Crash Decoding     : Disabled
  Default Encoding   : windows-1252
  MATLAB Architecture: win64
  MATLAB Root        : C:\Program Files\MATLAB\R2014a
  MATLAB Version     : 8.3.0.532 (R2014a)
  Operating System   : Microsoft Windows 7 Home Premium 
  Processor ID       : x86 Family 6 Model 60 Stepping 3, GenuineIntel
  Virtual Machine    : Java 1.7.0_11-b21 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode
  Window System      : Version 6.1 (Build 7601: Service Pack 1)

Fault Count: 1

Abnormal termination:
Unknown exception 0xe0434352

Register State (from fault):
  RAX = 00000006c5c7ffbf  RBX = 0000000000000001
  RCX = 00000006b3ffe180  RDX = 0000000000000128
  RSP = 00000006b3ffe790  RBP = 00000000000f8087
  RSI = 00000006b3ffe8f8  RDI = 0000000000000005

     R8 = 0000000000000000   R9 = 0000000000000000
    R10 = 0000000000000000  R11 = 00000006b3ffe7d0
    R12 = 0000000000004000  R13 = 0000000000000001
    R14 = 00000000e0434352  R15 = 00000000000f8087

    RIP = 000007fefcf3940d  EFL = 00000202

     CS = 0033   FS = 0053   GS = 002b

Stack Trace (from fault):
[  0] 0x000007fefcf3940d                 C:\Windows\system32\KERNELBASE.dll+00037901 RaiseException+00000061
[  1] 0x000007fef5955294 C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll+01397396 CopyPDBs+00039552
[  2] 0x000007fef595508e C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll+01396878 CopyPDBs+00039034
[  3] 0x000007feec39d54d C:\Windows\assembly\NativeImages_v4.0.30319_64\mscorlib\701f2b79b02a02beba70e50bb2edb212\mscorlib.ni.dll+20632909
[  4] 0x000007fe96314a60                                   <unknown-module>+00000000

If this problem is reproducible, please submit a Service Request via:
    http://www.mathworks.com/support/contact_us/

A technical support engineer might contact you with further information.

Thank you for your help.

Answer 1

[Guillaume]

Where do the q and a come from in your anonymous function?

As there is no point detecting file modifications while you're already processing them, I would disable the FileSystemWatcher at the beginning of importfcn and reenable it at the end. You could also check for modification right at the end of the function and process again if it has. Something like:

function importfcn(sender, eventargs)
   sender.EnableRaisingEvents = false; %disable filesystemwatcher
   %wait a little while to make sure modifications are complete
   fpath = fullfike(sender.Path, sender.Filter);
   oldmtime = System.IO.File.GetLastWriteTime(fpath);
   while true
       %process file
       newmtime = System.IO.File.GetLastWriteTime(fpath);
       if oldmtime.Equals(newmtime)
          break %file hasn't changed. break out of loop
       end
   end
   sender.EnableRaisingEvents = true;
end

warning: completely untested code. May contain bugs.