[lustre-discuss] Compile a C++ app. using the Lustre API

[Patrick Farrell]

It looks like your compiler is being fussier than the C compiler.


Specifically, the problem appears to be with the enum type.  The C compiler is happy to let pass using a short (cr_flags) where an enum is called for (argument to changelog_rec_offset).  In C, I think an enum is an int (so passing in a short like this is always fine).  I guess in C++ either enum is not an int, or it's just fussier.


There might be a compiler flag to make it not error on this?  I am not familiar with icpc, so I can't help with specifics.

You might also try a different C++ compiler, to see if it has a different attitude towards that error.


One further thought, though:
This is a C header.  Presumably, it is not intended to be included directly in a C++ project?


- Patrick

________________________________
From: lustre-discuss <lustre-discuss-bounces at lists.lustre.org> on behalf of François Tessier <ftessier at anl.gov>
Sent: Wednesday, March 15, 2017 2:00:31 PM
To: lustre-discuss at lists.lustre.org
Subject: [lustre-discuss] Compile a C++ app. using the Lustre API

Hi All,

I'm working on a piece of code using the Lustre API. To do so, I include
lustreapi.h. When I compile my code with a C compiler (icc), everything
is fine. However, when I compile it with a C++ compiler (icpc), I get
these errors:

---------------------------------

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(914): error: argument of type "__u16={unsigned short}" is incompatible with parameter of type "changelog_rec_flags"
         return changelog_rec_offset(rec->cr_flags);
                                     ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(925): error: a value of type "int" cannot be used to initialize an entity of type "changelog_rec_flags"
         enum changelog_rec_flags crf = rec->cr_flags & CLF_VERSION;
                                        ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(935): error: a value of type "int" cannot be used to initialize an entity of type "changelog_rec_flags"
         enum changelog_rec_flags crf = rec->cr_flags &
                                        ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(945): error: argument of type "int" is incompatible with parameter of type "changelog_rec_flags"
         return (char *)rec + changelog_rec_offset(rec->cr_flags &
                                                   ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(986): error: this operation on an enumerated type requires an applicable user-defined operator function
         crf_wanted &= CLF_SUPPORTED;
                    ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(997): error: argument of type "int" is incompatible with parameter of type "changelog_rec_flags"
                   changelog_rec_offset(crf_wanted & ~CLF_JOBID);
                                        ^

In file included from /usr/include/lustre/lustreapi.h(47),
                 from topo.c(5):
/usr/include/lustre/lustre_user.h(999): error: argument of type "int" is incompatible with parameter of type "changelog_rec_flags"
                   changelog_rec_offset(crf_wanted & ~(CLF_JOBID | CLF_RENAME));
                                        ^

Makefile:10: recipe for target 'topo' failed
make: *** [topo] Error 2

---------------------------------

It's probably more a compiler issue than a Lustre one but a solution
could help other users or Lustre developers.

Any idea?

Thanks,

François


--
--
François TESSIER, Ph.D.
Postdoctoral Appointee
Argonne National Laboratory
LCF Division - Bldg 240, 4E 19
Tel : +1 (630)-252-5068
http://www.francoistessier.info

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