Header file utils.hpp

namespace outcome_v2_xxx
    std::error_code error_from_exception(std::exception_ptr&& ep = std::current_exception(, std::error_code not_matched = std::make_error_code(std::errc::resource_unavailable_try_again) noexcept;

    void try_throw_std_exception_from_error(std::error_code ec, std::string const& msg = std::string{);

Function outcome_v2_xxx::error_from_exception

std::error_code error_from_exception(std::exception_ptr&& ep = std::current_exception(, std::error_code not_matched = std::make_error_code(std::errc::resource_unavailable_try_again) noexcept;

Utility function which tries to match the exception in the pointer provided to an equivalent error code. Ought to work for all standard STL types.

Effects: Rethrows the exception in the pointer, and via a long sequence of catch clauses attempts to match the equivalent error code. If a match is found, the pointer is reset to null. If a match is not found, not_matched is returned instead and the pointer is left unmodified.


  • ep — The pointer to an exception to convert. If matched, on exit this is reset to a null pointer.

Parameter outcome_v2_xxx::not_matched

std::error_code not_matched = std::make_error_code(std::errc::resource_unavailable_try_again

The error code to return if we could not match the exception.

Note that a null pointer in returns a null error code.

Function outcome_v2_xxx::try_throw_std_exception_from_error

void try_throw_std_exception_from_error(std::error_code ec, std::string const& msg = std::string{);

Utility function which tries to throw the equivalent STL exception type for some given error code, not including system_error.

Effects: If the input error code has a category of generic_category() (all platforms) or system_category() (POSIX only), throw the STL exception type matching the errno domained code if one is available. For example, ENOMEM would cause std::bad_alloc() to be thrown.


  • ec — The error code to try to convert into a STL exception throw.
  • msg — Optional custom message for the STL exception type.