Conversion of CString to std::string without 'GetString()'

Question

if m_attr.GetValue() returns a CString then:

why does the below code work without error message ... only warning message 'C4927'?

std::string sigCncDialog::GetSignalAttributeValue()
{return m_attr.GetValue();}

the correct would be of course:

std::string sigCncDialog::GetSignalAttributeValue()
{return m_attr.GetValue().GetString();}

Mike Seymour · Accepted Answer · 2014-09-25 16:21:24Z

3

Because of two evils:

CString has a conversion operator allowing implicit conversion to a C-style character pointer
the compiler apparently allows an implicit conversion sequence to contain two user-defined conversions, CString -> const char* -> std::string, with just the warning you mention, even though such a conversion is forbidden by standard C++

answered Sep 25, 2014 at 16:08

Mike Seymour

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