boost::system::error_code::operator unspecified-bool-type()
I've found boost.system to be very useful for wrapping return codes from 3rd party libraries (e.g. libcurl). However, one problem I've encountered is that error_code's operator for boolean tests assumes that an error value of 0 == success. I've found it puzzling that this logic doesn't reside in the error_category, where it can be customized as needed. For instance, boolean tests could chain to a is_error() virtual method in the error_category, the default implementation of which preserves the current behavior: namespace boost { namespace system { class error_category : public noncopyable { public: // ... virtual bool is_error( int ev ) const { return ev != 0; } // ... }; class error_code { public: // ... operator unspecified-bool-type() const { return m_cat->is_error( m_val ) ? unspecified_bool_true : 0; } // ... }; } } Is there any reason this was not done? What do people think about adding it in a future release? Matt
Gruenke, Matt wrote:
problem I've encountered is that error_code's operator for boolean tests assumes that an error value of 0 == success. I've found it puzzling that this logic doesn't reside in the error_category, where it can be customized as needed.
[snip]
class error_category : public noncopyable { public: virtual bool is_error( int ev ) const { return ev != 0; } };
class error_code { public: operator unspecified-bool-type() const { return m_cat->is_error( m_val ) ? unspecified_bool_true : 0; } };
That looks like an excellent addition that would increase the applicability. _____ Rob Stewart robert.stewart@sig.com Software Engineer, Core Software using std::disclaimer; Susquehanna International Group, LLP http://www.sig.com IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.
participants (2)
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Gruenke, Matt -
Stewart, Robert