Put back the specified character if it matches the previous character.
Move the current read position back one character if the current read position is not at the beginning of the buffer and the previous position contains the specified character c, and return that character. Otherwise, return traits_type::eof() and do not move the current read position.
c on success, or traits_type::eof() on failure
| Name | Description |
|---|---|
| c | character that must match the previous character in the buffer |