我正在尝试在OSX 10.11.3上构建Google OR-Tools示例
当我跑步时：
g++ -I../include/ -L../lib -lortools -Wno-c++11-extensions nqueens2.cc
In file included from nqueens2.cc:25:
In file included from ../include/constraint_solver/constraint_solver.h:65:
In file included from ../include/base/hash.h:19:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ext/hash_map:212:5: warning: Use of the header <ext/hash_map> is deprecated. Migrate to <unordered_map> [-W#warnings]
# warning Use of the header <ext/hash_map> is deprecated. Migrate to <unordered_map>
^
In file included from nqueens2.cc:25:
In file included from ../include/constraint_solver/constraint_solver.h:65:
In file included from ../include/base/hash.h:20:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ext/hash_set:205:5: warning: Use of the header <ext/hash_set> is deprecated. Migrate to <unordered_set> [-W#warnings]
# warning Use of the header <ext/hash_set> is deprecated. Migrate to <unordered_set>
^
In file included from nqueens2.cc:25:
In file included from ../include/constraint_solver/constraint_solver.h:65:
../include/base/hash.h:184:31: error: expected expression
struct hash<std::array<T, N>> {
^
../include/base/hash.h:201:2: error: expected a type
};
^
2 warnings and 2 errors generated.
我认为问题在于，当我希望编译器将其包含在
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ext/hash_map中时，它包括了../include。以下是导致错误的代码，来自
../include/base/hash.h（Google OR-Tools随附）：183 template <class T, std::size_t N>
184 struct hash<std::array<T, N>> {
185 public:
186 size_t operator()(const std::array<T, N>& t) const {
187 uint64 current = 71;
188 for (int index = 0; index < N; ++index) {
189 const T& elem = t[index];
190 const uint64 new_hash = hash<T>()(elem);
191 current = operations_research::Hash64NumWithSeed(current, new_hash);
192 }
193 return current;
194 }
195 // Less than operator for MSVC.
196 bool operator()(const std::array<T, N>& a, const std::array<T, N>& b) const {
197 return a < b;
198 }
199 static const size_t bucket_size = 4; // These are required by MSVC
200 static const size_t min_buckets = 8; // 4 and 8 are defaults.
201 };
202 #endif // STLPORT
203 } // namespace HASH_NAMESPACE
有什么想法吗？
最佳答案
旧的g ++编译器不允许连续两个>用作模板声明，因为它显示为>>运算符。因此，当您的代码查看struct声明时，它将看到{大括号而不是>>运算符的表达式。后来的c ++标准对此进行了更改，而g ++也进行了相应的更改。
C ++ 03编译器要求将>>解释为右移运算符。这在C ++ 0x标准中已更改。
关于c++ - 如何修复Google OR-Tools中的C++ 03双尖括号模板语法错误？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/35419183/