The stderr for Microsoft Windows native commands is undesirably
buffered when they are executed on Cygwin shell, Like this:
$ uname -a
CYGWIN_NT-6.1 localhost 1.7.17(0.262/5/3) 2012-10-19 14:39 i686 Cygwin
$ which nslookup
/cygdrive/c/Windows/system32/nslookup
$ nslookup
...
> set q=hogehoge
> set q=fugafuga
> exit
unknown query type: hogehoge
unknown query type: fugafuga
$
The error messages "unknown query type" should comes just after
"set q=" input respectively.
Create a simple program as follows:
#include <stdio.h>
int main(void) {
fprintf(stderr, "hogehoge\n");
/* fflush(stderr); */
getchar();
fprintf(stderr, "fugafuga\n");
return 0;
}
Build the program by MSVC:
c:\>cl /?
Microsoft(R) 32-bit C/C++ Optimizing Compiler Version 14.00.50727.762 for 80x86
Copyright (C) Microsoft Corporation. All rights reserved.
On Microsoft's cmd, everything goes fine. On bash in Cygwin,
first waiting for input, then 2 lines are printed.
If I insert fflush just before getchar, it works well both environments.
Who is buffering the stderr output? Is there any workaround?
Best Regards.
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