FN_SETEMOD()
 SetNetwareErrorMode
------------------------------------------------------------------------------
 Syntax
 
       fn_setEMod( [ <nErrorMode> ] -> nPreviousErrorMode
 
 Arguments

      <nErrorMode> is the mode to set (0 - 2).  If omitted it
      defaults to 0.

 Returns

      The error mode setting prior to making this function call.

 Description

      This function call sets a mode that determines how the shell responds
      to DOS emulation call errors.  It has no effect on Netware specific
      calls.  DOS differentiates between normal errors and critical errors.
      Normal errors are listed in the DOS Technical Reference manual.
      Critical errors are typically nonrecoverable errors detected by DOS
      which then invoke the INT 24h Critical Error Handler.  Whether an
      error code or INT 24h in invoked is determined by the specific error.

      The shell has three error modes: 0, 1, and 2.

      Mode 0 is the default mode and follows the common response format
      used by DOS (i.e., "Abort, Retry, Fail?").

      Mode 1 causes the shell to not invoke the INT 24h handler, instead
      returning the NetWare error code for all file I/O in register AL.

      Mode 2 causes the shell to attempts to map the NetWare error code to
      a DOS errorcode and return that instead.

      Both error modes 1 and 2 will cause the shell to return error codes
      instead of invoking INT 24h on some, but not all, network errors.

      For an application that uses the DOS function calls (v3.0 and
      greater), the shell returns the standard DOS extended error codes.
      An application is free to install its own INT 24h Critical Error
      Handler.

      NOTE:  If an application running DOS 3.1 or greater users network-
      aware calls (extended open, etc.) it does not matter what the
      Netware Error Mode is set to.  The shell returns the same errors
      that DOS would in the same situation.  For example, if an
      application attempts to open a locked file, the shell will return
      a DOS Error 5, "Access Denied".

      It is also important to note that all Netware errors that go to
      the user screen go through INT 24h and, therefore, can be trapped
      and acted upon under program control using a critical error handler.

      The error mode is automatically reset to mode 0 whenever an End Of
      Job occurs.  A child process inherits the error mode set by its
      parent.  However, if a child process set the error mode, the error
      mode is not inherited by the parent.  When control returns from the
      parent to DOS, the error mode is reset to the default mode of 0.

 Examples

      The following are two examples of how modes 0, 1, and 2 handle errors:

      Example 1:   Noncritical file I/O: Application attempts to open
                   a file without having open privileges.

      Mode 0:  No error message.  Returns a DOS error 2 in AL.
      Mode 1:  Returns an extended error 130 in AL.
      Mode 2:  Returns a DOS error 2 in AL (because file I/O was
               noncritical).

      Example 2:  Netware critical file I/O:  Application attempts to
                  open (file handle) a file that is already open.
                                                  (If the open attempt uses extended modes, Netware
                                                  returns in DOS Error 5, "Access Denied".)

      Mode 0:  Network error:file in use during OPEN.  The shell
               invokes INT 24h and the following message appears on the
                                          screen:

                                     File=<filename> ... Abort, Retry, Ignore?

      Mode 1:  Returns an extended error 128 in AL.
      Mode 2:  Returns an extended error 128 in AL.


 Source: N:\SRC\CONNWS\EMODE.PRG

 Author: Steve Larsen