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 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.

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 "