INF: Spawned Processes Do Not Always Handle Signals Properly

ID Number: Q46383

4.00 5.00 5.10 6.00 6.00a 6.00ax 7.00

MS-DOS

Summary:

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 calls MS-DOS Interrupt 0x4B to spawn

"COMMAND /c TYPE TEST.TXT | MORE" gives the same results.

Additional reference words: 5.00 5.10 6.00 6.00a 6.00ax 7.00