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Section: 18.104.22.168 [istream.unformatted], 22.214.171.124.4 [ostream.seeks] Status: TC1 Submitter: Angelika Langer Opened: 1999-02-22 Last modified: 2017-02-03
Priority: Not Prioritized
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Currently, the standard does not specify how seekg() and seekp() indicate failure. They are not required to set failbit, and they can't return an error indication because they must return *this, i.e. the stream. Hence, it is undefined what happens if they fail. And they can fail, for instance, when a file stream is disconnected from the underlying file (is_open()==false) or when a wide character file stream must perform a state-dependent code conversion, etc.
The stream functions seekg() and seekp() should set failbit in the stream state in case of failure.
Add to the Effects: clause of seekg() in 126.96.36.199 [istream.unformatted] and to the Effects: clause of seekp() in 188.8.131.52.4 [ostream.seeks]:
In case of failure, the function calls setstate(failbit) (which may throw ios_base::failure).
Setting failbit is the usual error reporting mechanism for streams