std::basic_streambuf<CharT,Traits>::setg
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< cpp | io | basic streambuf
| protected: void setg( char_type* gbeg, char_type* gcurr, char_type* gend ); |
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Sets the values of the pointers defining the get area. Specifically, after the call eback() == gbeg, gptr() == gcurr, egptr() == gend
Parameters
| 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
(none)
Example
Run this code
#include <iostream> #include <sstream> class null_filter_buf : public std::streambuf { std::streambuf* src; char ch; // single-byte buffer protected: int underflow() { traits_type::int_type i; while ((i = src->sbumpc()) == '\0') ; // skip zeroes if (!traits_type::eq_int_type(i, traits_type::eof())) { ch = traits_type::to_char_type(i); setg(&ch, &ch, &ch+1); // make one read position available } return i; } public: 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); in.rdbuf(&buf); for(char c; in.get(c); ) std::cout << c; in.rdbuf(orig); } int main() { char a[] = "This i\0s \0an e\0\0\0xample"; std::istringstream in(std::string(std::begin(a), std::end(a))); filtered_read(in); }
Output:
This is an example
See also
| repositions the beginning, next, and end pointers of the output sequence (protected member function) |