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std::basic_...f::showmanyc(3) C++ Standard Libarystd::basic_...f::showmanyc(3) NAME std::basic_filebuf::showmanyc - std::basic_filebuf::showmanyc Synopsis protected: virtual std::streamsize showmanyc() 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 in_avail obtains the number of characters immediately available in the get area (public member function of std::basic_stream- buf<CharT,Traits>) readsome extracts already available blocks of characters (public member function of std::ba- sic_istream<CharT,Traits>) http://cppreference.com 2022.07.31 std::basic_...f::showmanyc(3)
NAME | Synopsis | Parameters | Return value | Notes | Example | Possible output: | See also
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