Double closing angle brackets (>>) generates syntax error

Issue

Eclipse (Luna, 4.4.2) tells me that I have a syntax error on the following line:

static_cast<Vec<int, DIM>>(a.mul(b));

I remembered that double closing angle brackets >> can lead to problems with some compilers, so I put a blank in between: > >. The syntax error disappears.

However, I have many >> in my program where no syntax error is detected, such as:

Node<Element<DIM>> * e= a.get();

Why do I get an error the above mentioned specific case? This is related to error: 'varName' was not declared in this scope, but I don't know why my compiler does accept a >> sometimes, but not always.

Solution

You have used a pre c++11 standard compiler. The older standard had a problem letting the parser disambiguate a pair of closing angle brackets >> used in a nested template type specifier, from the operator>>(). Thus you had to write a space between them.

The samples like >>> or >>* are falling under a different case for the old parsers, thus they work without error message.

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_{I have to admit, I don't actually know what exactly was done in the c++11 (the current) standards definitions, that this situation can be clearly disambiguated by a c++11 compliant parser.}

Answered By - πάντα ῥεῖ