C++11 Type Deduction and Uniform Initialization

[Breannan_S_]

The following code fails to compile with icpc version 16.0.2 20160204 on OS X 10.11.4, but compiles fine with Clang and GCC:

#include <iostream>
#include <map>

int main( int argc, char** argv )
{
  std::map<int,int> test_map{ {1,2}, {3,4}, {5,6} };
  auto voxel_iterator{ test_map.find( 5 ) };
  //auto voxel_iterator = test_map.find( 5 );
  std::cout << voxel_iterator->first << " -> " << voxel_iterator->second << std::endl;
}

I receive the following error when compiling the code with 'icpc -std=c++11 main.cpp':

main.cpp(8): error: expression must have pointer type
    std::cout << voxel_iterator->first << " -> " << voxel_iterator->second << std::endl;
                 ^

main.cpp(8): error: expression must have pointer type
    std::cout << voxel_iterator->first << " -> " << voxel_iterator->second << std::endl;

It seems that icpc is not deducing the return type of find as an iterator when uniform initialization syntax is used. Replacing uniform initialization with '=' (see the commented line) results in the correct type deduction. Is this the expected behavior with uniform initialization?

[Judith_W_Intel]

Thanks for the report -- it looks like this was already recently reported here:

https://software.intel.com/en-us/forums/intel-c-compiler/topic/621832

It looks like this is only supported in GNU 5.0 and later versions, earlier versions of GNU give an error similar to icpc.

I can see that you've already identified an alternate syntax that you can use as a workaround.

Judy