std::basic_filebuf::showmanyc
From cppreference.com
< cpp | io | basic filebuf
| protected: virtual std::streamsize showmanyc() |
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If implemented, returns the number of characters left to read from the file.
Parameters
(none)
Return value
The number of characters available for reading from the file, or -1 if the end of file was reached.
Notes
This function is optional. If not implemented, this function returns 0 (since the base class version std::basic_streambuf::showmanyc gets called)
Whether implemented or not, this function is normally called by std::basic_streambuf::in_avail if the get area is empty.
The name of this function stands for "stream: how many characters?", so it is pronounced "S how many C", rather than "show many C"
Example
implementation test to see if showmanyc() is implemented for filebuf
Run this code
#include <fstream> #include <iostream> struct mybuf : std::filebuf { using std::filebuf::showmanyc; }; int main() { mybuf fin; fin.open("main.cpp", std::ios_base::in); std::cout << "showmanyc() returns " << fin.showmanyc() << '\n'; }
Possible output:
showmanyc() returns 267
See also
| obtains the number of characters immediately available in the get area (public member function of std::basic_streambuf) | |
| extracts already available blocks of characters (public member function of std::basic_istream) |