Mail Archives: cygwin/2006/02/27/19:08:57
On Mon, 27 Feb 2006, Mary Cuper wrote:
> I want to set the baudrate of my /dev/ttyS0 with:
>
> cfsetispeed(&options, B9600);
> cfsetospeed(&options, B9600);
>
> but always get:
>
> "Warning: right-hand operand of comma has no effect".
>
> With linux the code functions!
Cygwin uses newlib, which defines cfsetospeed as a macro that expands to
(foo, 0). "foo" is the part that does the actual work. g++ is simply
warning you that the "0" has no effect in void context (since you're
throwing away the return code). Linux uses glibc, which defines
cfsetospeed as a real function.
You can safely ignore this warning. If you want to get rid of it, cast
the return value to void, i.e.,
(void)cfsetospeed(&options, B9600);
or use the result in some expression.
Igor
--
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