Returns the transformation of c to its equivalent using the ctype::narrow facet of the locale object currently imbued in the stream, if such an equivalence exists, or dfault otherwise.
This function is designed for instantiations of basic_ios that use a different (wider) character type: see basic_ios::narrow
Parameters
c
Character to be "narrowed".
dfault
Character returned if c has no standard equivalent.
Return Value
The narrow equivalent of c, if any. Otherwise, it returns dfault.
Data races
Accesses the stream object.
Concurrent access to the same stream object may cause data races.
Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the stream.