#13359: GHCi crash in a standard Windows console (cmd.exe) after Control-c -------------------------------+---------------------------------------- Reporter: vanto | Owner: (none) Type: bug | Status: upstream Priority: normal | Milestone: Component: GHCi | Version: 8.0.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: GHCi crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------+---------------------------------------- Changes (by Phyx-): * status: new => upstream * architecture: x86 => Unknown/Multiple Comment: Thanks for the report, this seems to be an issue with the mingw-w64 runtime. I haven't narrowed it down yet, but essentially something seems to be eating the events and it never reaches ghci. `CtrlHandler` is never called. The following example shows the issue. It works when compiled using the Microsoft compiler but doesn't with mingw-w64's GHC. {{{ #include <windows.h> #include <stdio.h> BOOL CtrlHandler( DWORD fdwCtrlType ) { switch( fdwCtrlType ) { // Handle the CTRL-C signal. case CTRL_C_EVENT: printf( "Ctrl-C event\n\n" ); Beep( 750, 300 ); return( TRUE ); // CTRL-CLOSE: confirm that the user wants to exit. case CTRL_CLOSE_EVENT: Beep( 600, 200 ); printf( "Ctrl-Close event\n\n" ); return( TRUE ); // Pass other signals to the next handler. case CTRL_BREAK_EVENT: Beep( 900, 200 ); printf( "Ctrl-Break event\n\n" ); return FALSE; case CTRL_LOGOFF_EVENT: Beep( 1000, 200 ); printf( "Ctrl-Logoff event\n\n" ); return FALSE; case CTRL_SHUTDOWN_EVENT: Beep( 750, 500 ); printf( "Ctrl-Shutdown event\n\n" ); return FALSE; default: return FALSE; } } int main( void ) { if( SetConsoleCtrlHandler( (PHANDLER_ROUTINE) CtrlHandler, TRUE ) ) { printf( "\nThe Control Handler is installed.\n" ); printf( "\n -- Now try pressing Ctrl+C or Ctrl+Break, or" ); printf( "\n try logging off or closing the console...\n" ); printf( "\n(...waiting in a loop for events...)\n\n" ); while( 1 ){ } } else { printf( "\nERROR: Could not set control handler"); return 1; } return 0; } }}} This also doesn't work in an msys2 console, even though it appears to. In the case of msys2 bash is disabling `ENABLE_PROCESSED_INPUT` so that `CTRL+C` is not processed by the system and is reported as a input stream. Bash is then just terminating the process by force. In the case of GHCi, something does clearly happen with the runtime since it suddenly starts allocating a large amount of memory and enters some kind of deadlock. So there are two separate issues here. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13359#comment:1> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

#13359: GHCi crash in a standard Windows console (cmd.exe) after Control-c -------------------------------+---------------------------------------- Reporter: vanto | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: Component: GHCi | Version: 8.0.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: GHCi crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3292 Wiki Page: | -------------------------------+---------------------------------------- Changes (by Phyx-): * status: new => patch * differential: => Phab:D3292 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13359#comment:3> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler