char* str(); |
Returns the pointer to the beginning of the buffer, after freezing it. Effectively calls rdbuf()->str()
.
(none).
Pointer to the beginning of the buffer in the associated std::strsteambuf
or a null pointer if no buffer is available.
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 manipulator 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.
#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 "
marks the buffer frozen and returns the beginning pointer of the input sequence (public member function of std::strstreambuf ) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/io/ostrstream/str