# std::ostrstream::freeze

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< cpp‎ | io‎ | ostrstream

void freeze(bool flag = true); |  |

If the stream is using a dynamically-allocated array for output, disables (flag == true) or enables (flag == false) automatic allocation/deallocation of the buffer. Effectively calls rdbuf()->freeze(flag)

### Notes

After a call to str(), dynamic streams become frozen automatically. 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.

### Parameters

flag | - | desired status

### Return value

(none)

### Example

Run this code

    #include <strstream>
    #include <iostream>

    int main()
    {
        std::ostrstream dyn; // dynamically-allocated output buffer
        dyn << "Test: " << 1.23; // note: no std::ends to demonstrate appending
        std::cout << "The output stream contains \"";
        std::cout.write(dyn.str(), dyn.pcount()) << "\"\n";
        // the stream is now frozen due to str()
        dyn << " More text"; // output to a frozen stream may be truncated
        std::cout << "The output stream contains \"";
        std::cout.write(dyn.str(), dyn.pcount()) << "\"\n";
        dyn.freeze(false); // freeze(false) must be called or the  destructor will leak

        std::ostrstream dyn2; // dynamically-allocated output buffer
        dyn2 << "Test: " << 1.23; // note: no std::ends
        std::cout << "The output stream contains \"";
        std::cout.write(dyn2.str(), dyn2.pcount()) << "\"\n";
        dyn2.freeze(false);   // unfreeze the stream after str()
        dyn2 << " More text" << std::ends; // output will not be truncated (buffer grows)
        std::cout << "The output stream contains \"" << dyn2.str() << "\"\n";
        dyn2.freeze(false); // freeze(false) must be called or the  destructor will leak
    }

Possible output:

    The output stream contains "Test: 1.23"
    The output stream contains "Test: 1.23 More "
    The output stream contains "Test: 1.23"
    The output stream contains "Test: 1.23 More text"

### See also

freeze | sets/clears the frozen state of the buffer (public member function of `std::strstreambuf`)

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