std::ostrstream::str
| char* str();
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Returns the pointer to the beginning of the buffer, after freezing it. Effectively calls rdbuf()->str()
Contents |
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 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.
[edit] Parameters
(none)
[edit] Return value
Pointer to the beginning of the buffer in the associated std::strsteambuf or NULL if no buffer is available.
[edit] Example
#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
| marks the buffer frozen and returns the beginning pointer of the input sequence (public member function of std::strstreambuf)
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