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virtual int_type pbackfail(int_type c = Traits::eof());
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pbackfail()is called with no arguments). In this situation, the purpose of
pbackfail()is to back up the get area by one character, if the associated character sequence allows this (e.g. a file-backed streambuf may reload the buffer from a file, starting one character earlier).
pbackfail()is called with the character that needs to be put back). In this situation, the purpose of
pbackfail()is to place the character
cinto the get area at the position just before basic_streambuf::gptr(), and, if possible, to modify the associated character sequence to reflect this change. This may involve backing up the get area as in the first variant.
The default base class version of this function does nothing and returns Traits::eof() in all situations. This function is overloaded by the derived classes: basic_stringbuf::pbackfail, basic_filebuf::pbackfail, strstreambuf::pbackfail, and is expected to be overloaded by user-defined and third-party library stream classes.
|ch||-||character to put back or Traits::eof() if only back out is requested|
Traits::eof() in case of failure, some other value to indicate success. The base class version always fails.
|This section is incomplete|
Reason: no example