我正在阅读Vandevoorde和Josuttis的“C模板完整指南”(顺便说一句,这看起来还不错).这个说法(第3.3节)似乎是错误的
and is not in the published errata:
If you specialise a class template,you must also specialise all member functions. Although it is possible to specialise a single member function,once you have done so,you can no longer specialise the whole class.
然而以下编译在gcc上
模板
<typename T> struct C { T foo (); T bar (); }; template <> struct C<int> { int foo (); int bar () {return 4;} }; template <typename T> T C<T> :: foo () {return 0;} template <typename T> T C<T> :: bar () {return 1;} int C<int> :: foo () {return 2;} template <> float C<float> :: bar () {return 3;} #include <cassert> int main () { C<int> i; C<float> f; assert (2 == i .foo ()); assert (0 == f .foo ()); assert (4 == i .bar ()); assert (3 == f .bar ()); }
我有专门的C< int> :: foo和C< float> :: bar所以教科书错了,gcc超出了标准,还是我误解了整个情况?
谢谢.
解决方法
你不能做这个:
template <typename T> struct C { T foo () { return 0;} T bar () { return 1;} }; // partial specialization of foo on C<int> template <> int C<int> :: foo () {return 2;} // partial specialization of bar on C<float> template <> float C<float> :: bar () {return 3;} // will not compile,C<int> already partially specialized template <> struct C<int> { int foo() {return 10;} int bar() {return 10;} };
原文地址:https://www.jb51.cc/c/110312.html
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