https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85729
Bug ID: 85729
Summary: including c++ headers within extern "C" linkage
specification
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: nsz at gcc dot gnu.org
Target Milestone: ---
some code does not include c++ headers in the top level but has
extern "C" {
#include <cstring>
}
this is invalid c++ (similar to bug 19373 where the include is under
namespace specification), but this can be made to work for c*
headers by adding explicit extern "C++" annotations where necessary
in libstdc++ headers. (currently it happens to work with a normal
gnu toolchain, because then glibc provides the string function
prototypes with explicit extern "C++", but with other setups it
can fail.)
alternatively gcc could try to warn about such header usage,
the relevant text in the spec is
[using.headers]:
A translation unit shall include a header only outside of any external
declaration or definition, and shall include the header lexically
before the first reference in that translation unit to any of the
entities declared in that header. No diagnostic is required.
