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c++c++17guideline-support-library

gsl::fail_fast not found in the namespace

In this simple use of C++ contracts, I get the error: no type named 'fail_fast' in namespace 'gsl'. Will try block throw the fast_fail exception or some other exception?

#define GSL_THROW_ON_CONTRACT_VIOLATION
#include <gsl/gsl>
#include <iostream>


int main(void)
{
    try {
        Expects(false);
    }
    catch(const gsl::fail_fast &e) {
        std::cout << "exception: " << e.what() << '\n';
    }
}
Solution

  • GSL_THROW_ON_CONTRACT_VIOLATION and gsl::fast_fail were removed from the Microsoft GSL starting with release v3.0.0. All contract violations result in a call to std::terminate unless you are building in kernel mode for MSVC where it invokes __fastfail.

    Header file gsl_assert.h only defines gsl::fail_fast exception with GSL_THROW_ON_CONTRACT_VIOLATION defined. So it compiles now? – Serve Laurijssen

    There was a period of time where gsl::fast_fail was defined only when GSL_THROW_ON_CONTRACT_VIOLATION was defined, however that was identified in #267 and subsequently fixed in #268.