c++ - Is auto as a parameter in a regular function a GCC 4.9 extension? -

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gcc 4.9 allows following code, gcc 4.8 , clang 3.5.0 reject it.

void foo(auto c) {     std::cout << c.c_str(); }

i warning: iso c++ forbids use of 'auto' in parameter declaration [-wpedantic] in 4.9 in 4.8 , clang error: parameter declared 'auto'.

yes, extension. it's added c++17 part of 'concepts' proposal, believe.


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