FIX: The select( ) function and the write( ) function do not handle the non-blocking serial I/O correctly (889087)

SYMPTOMS

The migration of the Portable Operating System Interface for UNIX (POSIX) subsystems from SCO to Interix is held up because of one of the following conditions:

The select() function incorrectly indicates that the serial port is ready for the write operation even though it is not yet ready. The select() function also does not work when you set the action parameter of the tcflow() function to TCOOFF or TCOON.

Note The TCOOFF action parameter value is for suspending output. The TCOON action parameter value is for restarting suspended output.
The write() function blocks when the serial device is not ready. This behavior occurs even if the O_NONBLOCK flag is set. This problem can occur at the start of the write operation or if the device is disconnected during the write operation.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next release that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Restart requirement

You must restart your computer because the POSIX subsystem is replaced when you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version      Size     File name     
   ----------------------------------------------------
   09-Nov-2004  04:51  8.0.1969.20  130,048  Posix.exe 
   09-Nov-2004  04:51  8.0.1969.20  104,448  Psxrun.exe 
   09-Nov-2004  04:51  8.0.1969.20  763,904  Psxss.exe