Re: [libmicrohttpd] enum arguments for MHD_start_daemon

[Christian Grothoff]

On 08/20/2012 08:29 AM, Martin Velek wrote:
> Hello,
>
> I am trying to use this library(libmicrohttpd-0.9.9.tar.gz) with LWIP
> and FreeRTOS on LPC2478. Due to limited resources I have enabled an
> option "-fshort-enums" (use as small as possible size to hold values
> from enum). Similar post has been already written - see
> http://lists.gnu.org/archive/html/libmicrohttpd/2012-06/msg00001.html
>
> During compilation these warning messages appear ( arm-none-eabi-gcc,
> gcc version 4.6.1 (Sourcery CodeBench 2011.09-60)):
> ../Source/Library/libmicrohttpd/daemon.c: In function 'parse_options_va':
> ../Source/Library/libmicrohttpd/daemon.c:1651:35: warning: 'enum
> MHD_OPTION' is promoted to 'int' when passed through '...' [enabled by
> default]
> ../Source/Library/libmicrohttpd/daemon.c:1651:35: note: (so you should
> pass 'int' not 'enum MHD_OPTION' to 'va_arg')
> ../Source/Library/libmicrohttpd/daemon.c:1651:35: note: if this code
> is reached, the program will abort
>
> It meants that the enum MHD_OPTION is threated as uint8. But when
> parameters are extracted, these are threated as int.
>
> "simon h" has suggested to use a special option MHD_OPTION_FORCE32 =
> 0xFFFFFFFFUL. I would vote for this to overcome this issue.
Would it not be simpler (and possibly more efficient) to just use 'int' 
instead of 'enum MHD_OPTION' as suggested by the compiler's warning? I'd 
certainly be willing to do that instead as well...

Happy hacking.

Christian