Q46383: Spawned Processes Do Not Always Handle Signals Properly

Article: Q46383
Product(s): See article
Version(s): 4.x 5.00 5.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | S_QuickC | mspl13_c
Last Modified: 9-AUG-1989

In the following example, the CTRL+C signal is not handled as expected
within the spawned process:

    #include <stdio.h>
    #include <process.h>

    void main( void )
    {
        int err;

        err = system( "TYPE TEST.TXT | MORE" );

        printf( "Return from system: %d\n", err );
    }

If CTRL+C is pressed while the file is being typed, temporary files
used by MORE to emulate pipes are left in the root of the current
drive. The return value from the system does not indicate any
problems.

This is a limitation of MS-DOS and the way child processes handle
certain signals, not a problem with the C compiler. Interrupting an
assembly language program that simply calls DOS interrupt 0x4B to
spawn "COMMAND /c TYPE TEST.TXT | MORE" gives the same results.

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