std::strstreambuf::str
| I/O manipulators | ||||
| Print functions (C++23) | ||||
| C-style I/O | ||||
| Buffers | ||||
(C++23) | ||||
(C++98/26*) | ||||
(C++20) | ||||
| Streams | ||||
| Abstractions | ||||
| File I/O | ||||
| String I/O | ||||
| Array I/O | ||||
(C++23) | ||||
(C++23) | ||||
(C++23) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
(C++98/26*) | ||||
| Synchronized Output | ||||
(C++20) | ||||
| Types | ||||
| Error category interface | ||||
(C++11) | ||||
(C++11) |
| Public member functions | ||||
strstreambuf::str | ||||
| Protected member functions | ||||
| char* str(); |
(deprecated in C++98) (removed in C++26) |
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Calls freeze(), then returns a copy of start pointer of the get area, std::streambuf::eback().
The start of the get area, for all writeable std::strstreambuf objects constructed through the interface provided by std::strstream, is also the start of the put area.
Contents |
[edit] Parameters
(none)
[edit] Return value
A copy of eback(), which may be a null pointer.
[edit] Notes
This function is typically called through the std::strstream interface.
The call to freeze() guarantees that the returned pointer remains valid until the next explicit call to freeze(false): otherwise (on a dynamic buffer) any output operation could trigger buffer reallocation which would invalidate the pointer. It also causes a memory leak in the destructor of std::strstreambuf, unless freeze(false) is called before the buffer (or, more commonly, the std::strstream that manages it) is destroyed.
[edit] Example
#include <iostream> #include <strstream> int main() { std::strstream dyn; / dynamically-allocated read/write buffer dyn << "Test: " << 1.23 << std::ends; std::strstreambuf* buf = dyn.rdbuf(); std::cout << "R/W buffer holds [" << buf->str() / or dyn.str() << "]\n"; dyn.freeze(false); / after calling .str() on a dynamic strstream char arr[10]; std::ostrstream user(arr, 10); / fixed-size write-only buffer buf = user.rdbuf(); user << 1.23 << std::ends; std::cout << "Write-only buffer holds [" << buf->str() / or user.str() << "]\n"; std::istrstream lit("1 2 3"); / fixed-size read-only buffer buf = lit.rdbuf(); std::cout << "Read-only buffer holds [" << buf->str() / or lit.str() << "]\n"; }
Output:
R/W buffer holds [Test: 1.23] Write-only buffer holds [1.23] Read-only buffer holds [1 2 31 2 3]
[edit] See also
| accesses the output buffer (public member function of std::strstream) [edit]
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| accesses the output buffer (public member function of std::ostrstream) [edit]
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| accesses the output buffer (public member function of std::istrstream) [edit]
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