Put back one byte of input, optionally substituting a character.
Declared in <bdlde_utf8checkinginstreambufwrapper.h>
virtual
int_type
pbackfail(int_type c = traits_type::eof()) override;Back up input one byte. Return the byte at the new position, or eof with the state of this object unchanged on failure. If the optionally specified c is not eof, substitute c for the previous byte and return that value. If c is eof, do not substitute it for the previous byte and return the byte was there, or if the previous byte is unknown, fail. If values of c that are not eof are specified, this function will succeed for at least 8 successive calls, possibly many more times. The behavior is undefined unless c is either eof or a value representable as a char_type. Note that this is forwarded to with a char_type passed to c by the public method sputbackc in the base class, and called with eof passed to c by the public method sungetc in the base class.
the byte at the new position, or eof on failure
| Name | Description |
|---|---|
| c | character to substitute for the previous byte, or eof to leave the previous byte unchanged |