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  1. #include <iostream>
  2. #include <sstream>
  3.  
  4. int main(int argc, const char * argv[]) 
  5. {
  6.     std::stringstream a;
  7.     std::stringstream b;
  8.     std::stringstream c;
  9.     std::stringstream out;
  10.  
  11.     a << "abc";
  12.     b << "";
  13.     c << "xyz";
  14.  
  15.     out << a.rdbuf();
  16.     printf("after A out.tellp = %qd\n", (int64_t)out.tellp());
  17.  
  18.     out << b.rdbuf();
  19.     if( ! out.good() )
  20. 	{
  21. 		std::cout<< "It is not good!!!" << std::endl;
  22. 		out.clear();
  23. 	}
  24.     printf("after B out.tellp = %qd\n", (int64_t)out.tellp());
  25.  
  26.     out << c.rdbuf();
  27.     printf("after C out.tellp = %qd\n", (int64_t)out.tellp());
  28.  
  29.     std::cout << out.rdbuf() << std::endl;
  30.  
  31.     return 0;
  32. }
Success #stdin #stdout 0s 4476KB
comments (?)
stdin
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Standard input is empty
stdout
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after A out.tellp = 3
It is not good!!!
after B out.tellp = 3
after C out.tellp = 6
abcxyz
https://ideone.com/KVXfrz
https://stackoverflow.com/questions/59145029/appending-an-ostream-which-is-the-empty-string-prevents-further-appends
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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