Strange error when compiling minimal GSSAPI application

[Benjamin Kaduk]

On Sat, 16 Mar 2013, Elias Mårtenson wrote:

> Is there a problem with the GSSAPI implementation in FreeBSD?

There might be; I can't remember if I had trouble with it in my current 
application even before I started using the gss_pseudo_random feature 
which it does not support (which caused me to switch to the MIT krb5 
implementation).

> I'm trying to compile a minimal application that does nothing more than
> including the file gssapi/gssapi_krb5.h:
>
>    #include <gssapi/gssapi_krb5.h>
>
>    int main(void)
>    {
> return 0;
>    }

You do not mention which version of FreeBSD you are using.

> When compiling this with "gcc foo.c" I get the following error:
>
>    In file included from foo.c:1:
>    /usr/include/gssapi/gssapi_krb5.h:139: error: expected declaration
> specifiers or '...' before 'time_t'

I find that clang's warning/error messages are frequently more helpful 
than gcc's.  Running the same experiment on my 10-current (r247267) setup 
I get a somewhat different error:
/usr/include/gssapi/gssapi_krb5.h:56: error: expected '=', ',', ';', 'asm' 
or '__attribute__' before 'extern'

It seems that GSSAPI_CPP_START is never defined, for one.

> I have to admit that I'm a bit stumped as to why I get the error message in
> the first place. The line in question looks like this:
>
>    OM_uint32
>    gsskrb5_extract_authtime_from_sec_context(OM_uint32 *, gss_ctx_id_t,
> time_t *);
>
> I checked the preprocessor output and there are indeed correct typedefs for
> OM_uint32, gss_ctx_id_t and time_t, so I can't really see why this error
> would occur.

The previous line may also be relevant.  You do not have any 
GSSAPI_LIB_FUNCTION or GSSAPI_LIB_CALL macros in the type specification of 
the function, though?  (I do.)

> In any case, given the import program, this behaviour isn't really correct
> as far as I can tell.
>
> Any input on this?

The provided gssapi_krb5 support is certainly suboptimal -- including the 
header at all gives a warning that it uses the deprecated path "gssapi.h" 
to get the generic gssapi declarations.  Might be, it needs further love.

-Ben Kaduk