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C++ streambuf - sgetn
Description
It is used to get sequence of characters and calls the protected virtual member xsgetn with the same arguments s and n.
Declaration
Following is the declaration for std::basic_streambuf::sgetn.
streamsize sgetn (char_type* s, streamsize n);
Parameters
sPointer to an array where the character sequence is copied.
nMaximum number of characters to be retrieved.
Return Value
It returns the number of characters copied.
Exceptions
Basic guarantee − if an exception is thrown, the stream buffer is in a valid state.
Data races
It modifies up to all of the first n characters in the array pointed by s.
Example
In below example explains about std::basic_streambuf::sgetn.
#include <iostream> #include <fstream> int main () { char* contents; std::ifstream istr ("sample.txt"); if (istr) { std::streambuf * pbuf = istr.rdbuf(); std::streamsize size = pbuf->pubseekoff(0,istr.end); pbuf->pubseekoff(0,istr.beg); contents = new char [size]; pbuf->sgetn (contents,size); istr.close(); std::cout.write (contents,size); } return 0; }
streambuf.htm
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