https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69893
Bug ID: 69893 Summary: [6 Regression] Conflicting declarations in <math.h> and <parallel/algorithm> Product: gcc Version: 6.0 Status: UNCONFIRMED Keywords: rejects-valid Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: miyuki at gcc dot gnu.org CC: redi at gcc dot gnu.org Target Milestone: --- The following program used to work some time ago (with GCC 20160118), but with current version it is rejected: $ cat test.cc #include <math.h> #include <parallel/algorithm> $ cc1plus test.cc In file included from /opt/gcc-6.0.0/include/c++/6.0.0/tr1/random:46:0, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/random_number.h:36, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/partition.h:38, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/quicksort.h:36, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/sort.h:48, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/algo.h:45, from /opt/gcc-6.0.0/include/c++/6.0.0/parallel/algorithm:37, from test.cc:2: /opt/gcc-6.0.0/include/c++/6.0.0/tr1/cmath: In function 'float std::tr1::acosh(float)': /opt/gcc-6.0.0/include/c++/6.0.0/tr1/cmath:424:18: error: 'float std::tr1::acosh(float)' conflicts with a previous declaration acosh(float __x) ^ In file included from /opt/gcc-6.0.0/include/c++/6.0.0/math.h:36:0, from test.cc:1: /opt/gcc-6.0.0/include/c++/6.0.0/cmath:1224:3: note: previous declaration 'constexpr float std::acosh(float)' acosh(float __x) ^~~~~ ... (more errors follow)