sof 2005/05/05 17:30:58 PDT
Modified files:
libraries/base/GHC ConsoleHandler.hs
libraries/base/cbits consUtils.c
libraries/base/include consUtils.h
ghc/compiler/ghci InteractiveUI.hs
Log:
[mingw only]
Work around bug in win32 Console API which showed up in the GHCi UI:
if the user typed in characters prior to the appearance of the prompt,
the first of these characters always came out as a 'g'. The GHCi UI does
for good reasons one-character reads from 'stdin', which causes the
underlying APIs to become confused. A simple repro case is the following
piece of C code:
/*----------------------*/
#include <stdio.h>
#include <windows.h>
int main()
{
char ch1,ch2;
HANDLE hStdIn = GetStdHandle(STD_INPUT_HANDLE);
DWORD dw;
/* Type in some characters before the prompt appears and be amused.. */
sleep(1000); printf("? ");
ReadConsoleA(hStdIn,&ch1,1,&dw,NULL);
ReadConsoleA(hStdIn,&ch2,1,&dw,NULL);
/* or, if you want to use libc:
read(0,&ch1,1); read(0,&ch2,1); */
printf("%c%c\n", ch1,ch2);
return 0;
}
/*----------------------*/
This happens across win32 OSes, and I can't see anything untoward as far
as API usage goes (the GHC IO implementation uses read(), but that
reduces to ReadConsoleA() calls.) People inside the Behemoth might want
to have a closer look at this..
Not much we can do about this except work around the problem by flushing
the input buffer prior to reading from stdin. Not ideal, as type-ahead
is a useful feature. Flushing is handled by GHC.ConsoleHandler.flushConsole
Merge to STABLE.
Revision Changes Path
1.8 +13 -0 fptools/libraries/base/GHC/ConsoleHandler.hs
1.5 +13 -0 fptools/libraries/base/cbits/consUtils.c
1.2 +1 -0 fptools/libraries/base/include/consUtils.h
1.203 +9 -0 fptools/ghc/compiler/ghci/InteractiveUI.hs
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