The protected virtual member function tries to put back an element into the input buffer, and then make it the current element (pointed to by the next pointer).
virtual int_type pbackfail(
int_type _Meta = traits_type::eof( )
);
Parameters
- _Meta
The character to insert into the buffer, or traits_type::eof.
Return Value
If the function cannot succeed, it returns traits_type::eof. Otherwise, it returns traits_type::not_eof(_Meta).
Remarks
If _Meta compares equal to traits_type::eof, the element to push back is effectively the one already in the stream before the current element. Otherwise, that element is replaced by byte = traits_type::to_char_type(_Meta). The function can put back an element in various ways:
If a putback position is available, and the element stored there compares equal to byte, it can decrement the next pointer for the input buffer.
If a putback position is available, and if the stringbuf mode permits the sequence to be altered (mode & ios_base::out is nonzero), it can store byte into the putback position and decrement the next pointer for the input buffer.
Requirements
Header: <sstream>
Namespace: std