[sane-devel] scan can not be stopped: possible problems with sanei_thread?

Oliver Rauch Oliver.Rauch at Rauch-Domain.DE
Sat Sep 15 15:49:05 UTC 2007


After an update to the cvs version of sane-backends I released that it
is not possible to stop a scan or a preview scan any more with the umax
backend. This is tested with scanimage and xsane.

AFAIR I did not make any changes relevant to this points in the umax
backend or in xsane. (And scanimage has the same problem).

To stop a scan in the umax backend the function sane_cancel calls
do_cancel that uses sanei_thread to kill the reader process and waits
for the reader process. But sanei_thread_waitpid() never returns.

Here is the relevant code in do_cancel:

static SANE_Status do_cancel(Umax_Scanner *scanner)
int pid, status;


  scanner->scanning = SANE_FALSE;

  if (scanner->reader_pid > 0)
    DBG(DBG_sane_info,"killing reader_process\n");

    pid = sanei_thread_waitpid(scanner->reader_pid, &status);

Does anyone remember a change that could have caused this problem?
Does anyone has also problems to stop a scan or preview scan?
Does anyone know from which sane-backends version it stopped working?

Note: USE_PTHREAD is not defined

Best regards

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