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std::ostrstream::str(3) C++ Standard Libary std::ostrstream::str(3) NAME std::ostrstream::str - std::ostrstream::str Synopsis char* str(); Returns the pointer to the beginning of the buffer, after freezing it. Effectively calls rdbuf()->str() Parameters (none) Return value Pointer to the beginning of the buffer in the associated std::strsteambuf or a null pointer if no buffer is available. Notes Before a call to str() that uses the result as a C string, the stream buffer must be null-terminated. Regular output such as with stream << 1.2 does not store a null terminator, it must be appended explicitly, typically with the ma- nipulator std::ends. After a call to str(), dynamic streams become frozen. A call to freeze(false) is required before exiting the scope in which this ostrstream object was created. otherwise the destructor will leak memory. Also, additional output to a frozen stream may be truncated once it reaches the end of the allocated buffer, which may leave the buffer not null-terminated. Example // Run this code #include <strstream> #include <iostream> int main() { std::ostrstream dyn; // dynamically-allocated output buffer dyn << "Test: " << 1.23; // not adding std::ends to demonstrate append behavior std::cout << "The output stream holds \""; std::cout.write(dyn.str(), dyn.pcount()) << "\"\n"; // the stream is now frozen due to str() dyn << " More text" << std::ends; std::cout << "The output stream holds \""; std::cout.write(dyn.str(), dyn.pcount()) << "\"\n"; dyn.freeze(false); } Possible output: The stream holds "Test: 1.23" The stream holds "Test: 1.23 More " See also str marks the buffer frozen and returns the beginning pointer of the input sequence (public member function of std::strstreambuf) http://cppreference.com 2022.07.31 std::ostrstream::str(3)
NAME | Synopsis | Parameters | Return value | Notes | Example | Possible output: | See also
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