<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div><br></div><div><br>On Sep 19, 2016, at 5:55 PM, Richard Smith via cfe-commits <<a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div>Your c.h is not correct. It would introduce a definition of c in every file where it's included, so it's not a modular header.<br></div></div></blockquote><div>Hi Richard,</div><div><br></div>What do you mean by c.h is not correct? It is guarded by a macro, so if we are not using modules, it will work.<div><br></div><div>Also I thought the definition of a non-modular header is that it is not mapped to any module. Is that my misunderstanding? Is there a formal definition for modular header?</div><div><br></div><div>Thanks,</div><div>Manman<br><blockquote type="cite"><div><div><div class="gmail_extra"><br><div class="gmail_quote">On 19 Sep 2016 5:21 pm, "Manman via cfe-commits" <<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Hi Richard & Ben,<br>
<br>
Given a simple testing case, where we have two submodules X.A (A.h) and X.B (B.h, it includes C.h, and C.h is guarded with a macro), when we import X.A and then textually include a header C.h, we get redefinition error. This is because the macro guard is owned by module X.B that is not yet visible. I wonder what the fix is if this is considered a compiler issue. We can:<br>
1> do not emit the redefinition error if the earlier definition is not visible, or<br>
2> emit diagnostics to suggest user to import the whole module, when redefinition happens because the module includes a non-modular header and the non-modular header is also textually included, or<br>
3> other suggestions?<br>
<br>
Note that if we textually include C.h, then import X.A, there are no compiler errors.<br>
<br>
The testing case here:<br>
clang -cc1 repro.c -fsyntax-only -I Inputs4/ -fmodules -fimplicit-module-maps -fmodules-cache-path=tmp<br>
cat repro.c<br>
#include "A.h" //modular header<br>
#include "C.h" //non-modular header<br>
<br>
cat Inputs4/module.map<br>
module X {<br>
module A {<br>
header "A.h"<br>
export *<br>
}<br>
module B {<br>
header "B.h"<br>
export *<br>
}<br>
export *<br>
}<br>
cat Inputs4/A.h<br>
#ifndef __A_h__<br>
#define __A_h__<br>
#endif<br>
cat Inputs4/B.h<br>
#ifndef __B_h__<br>
#define __B_h__<br>
#include "C.h"<br>
#endif<br>
cat Inputs4/C.h<br>
#ifndef __C_h__<br>
#define __C_h__<br>
int c = 1;<br>
const int d = 2;<br>
#endif<br>
<br>
Thanks,<br>
Manman<br>
______________________________<wbr>_________________<br>
cfe-commits mailing list<br>
<a href="mailto:cfe-commits@lists.llvm.org" target="_blank">cfe-commits@lists.llvm.org</a><br>
<a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits" rel="noreferrer" target="_blank">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/cfe-commits</a><br>
</blockquote></div></div>
</div>
</div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>cfe-commits mailing list</span><br><span><a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a></span><br><span><a href="http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits">http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits</a></span><br></div></blockquote></div></body></html>