std::basic_streambuf<CharT,Traits>::setg (3) - Linux Manuals

std::basic_streambuf<CharT,Traits>::setg: std::basic_streambuf<CharT,Traits>::setg


std::basic_streambuf<CharT,Traits>::setg - std::basic_streambuf<CharT,Traits>::setg


void setg( char_type* gbeg, char_type* gcurr, char_type* gend );

Sets the values of the pointers defining the get area. Specifically, after the call eback() == gbeg, gptr() == gcurr, egptr() == gend


gbeg - pointer to the new beginning of the get area
gcurr - pointer to the new current character (get pointer) in the get area
gend - pointer to the new end of the get area

Return value



// Run this code

  #include <iostream>
  #include <sstream>

  class null_filter_buf : public std::streambuf {
      std::streambuf* src;
      char ch; // single-byte buffer
      int underflow() {
          while( (ch= src->sbumpc()) == '\0') ; // skip zeroes
          setg(&ch, &ch, &ch+1); // make one read position available
          return ch; // may return EOF
      null_filter_buf(std::streambuf* buf) : src(buf) {
          setg(&ch, &ch+1, &ch+1); // buffer is initially full

  void filtered_read(std::istream& in)
      std::streambuf* orig = in.rdbuf();
      null_filter_buf buf(orig);
      for(char c; in.get(c); )
              std::cout << c;

  int main()
      char a[] = "This i\0s \0an e\0\0\0xample";
      std::istringstream in(std::string(std::begin(a), std::end(a)));


  This is an example

See also

     repositions the beginning, next, and end pointers of the output sequence
setp (protected member function)