Fix construction from empty arrays in debug modes #57
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Use .data() instead of &arr[0] to get the array pointer. This avoids calling operator[] with 0, which causes assertions in some debug modes to fail. For example when using -D_GLIBCXX_DEBUG for the libstdc++ debug mode. In Visual Studio, a similar debug mode is even the default for Debug builds, so this problem can occur quite easily.
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Thanks @mjacobse ! |
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I had issues when constructing spans from
std::arrays with size 0 in Visual Studio. In Debug builds it has its container debugging mode for the standard library enabled (_CONTAINER_DEBUG_LEVEL > 0) and breaks on an assertion error whenoperator[]is called with 0. I then tried the stdlibc++ debug mode (-D_GLIBCXX_DEBUG) and it shows the same problem. I guess that technically&arr[0]is not a bug, but practically it can become a problem with these debug modes. I couldn't think of a disadvantage of using.data(), so I propose to use that instead.