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Re: "cannot run C compiled programs" error
On 27 April 2011 06:11, Jeffrey Walton wrote:
> On Tue, Apr 26, 2011 at 8:55 AM, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
>>
>>>
>>>> [SNIP]
>>>>
>>>> Please try to reproduce the error with a minimal example to show
>>>> whether you get that error just from including a header, or only under
>>>> certain circumstances.
>>>
>>> I managed to track it down to the following test.cpp file:
>>>
>>> #include <cmath>
>>> #include <mgl/mgl.h>
>>> #include <algorithm>
>>>
>>> Where mgl is from the wxWidgets library, version 2.8.11
>>>
>>> When I changed the order to:
>>> #include <cmath>
>>> #include <algorithm>
>>> #include <mgl/mgl.h>
>>>
>>> It worked.
>>
>> That would imply the mgl.h header does something it shouldn't, such as
>> defining isnan as a macro, or something else which breaks the standard
>> library header.
>>
> I've also seen similar in the past. I seem to recall (like Anna) that
> the C++ gear had to be included before [some of] the standard linux
> stuff such as sys/types, sys/socket.h, and netinet/in.h. Fortunately,
> the standard linux headers do a good job of guarding for multiple
> definitions (when they follow C++ headers). The C++ headers, on the
> other hand, do not always do a good job (when they follow standard
> headers).
Examples please. That would be a serious bug and should be reported to
bugzilla rather than alluded to vaguely on a mailing list.
mgl/mgl.h is not "standard linux stuff" so we can't do anything about
that, but I'm pretty sure there are no conflicts between libstdc++
headers and glibc headers (when used correctly)