std::basic_stringbuf<CharT,Traits,Allocator>::str - cppreference.com (original) (raw)

Gets and sets the underlying string.

In the descriptions below, buf and mode are exposition-only data members of *this.

1. Creates and returns a std::basic_string object containing a copy of this std::basic_stringbuf's underlying character sequence. For input-only streams, the returned string contains the characters from the range [eback(), egptr()). For input/output or output-only streams, contains the characters from pbase() to the last character in the sequence regardless of egptr() and epptr().

The member character sequence in a buffer open for writing can be over-allocated for efficiency purposes. In that case, only the initialized characters are returned: these characters are the ones that were obtained from the string argument of the constructor, the string argument of the most recent call to a setter overload of str(), or from a write operation. A typical implementation that uses over-allocation maintains a high-watermark pointer to track the end of the initialized part of the buffer and this overload returns the characters from pbase() to the high-watermark pointer.

1. Same as (1), except that a is used to construct the returned std::basic_string. Equivalent to return std::basic_string<CharT, Traits, SAlloc>(view(), a);.

This overload participates in overload resolution only if SAlloc meets the requirements of Allocator.

1. Creates a std::basic_string object as if by move constructing it from *this's underlying character sequence in buf. buf may need to be adjusted to contain the same content as in (1) at first. After that, sets buf to empty and calls init_buf_ptrs(), then returns the std::basic_string object.

2. Replaces the underlying character sequence as if by buf = s, then calls init_buf_ptrs().

3. Same as (4), except the type of s's allocator is not Allocator.

This overload participates in overload resolution only if std::is_same_v<SAlloc, Allocator> is false.

1. Replaces the underlying character sequence as if by buf = std::move(s), then calls init_buf_ptrs().

2. Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then replaces the underlying character sequence as if by buf = sv, then calls init_buf_ptrs().

[edit] Parameters

[edit] Return value

1-3) A std::basic_string object holding this buffer's underlying character sequence.

4-7) (none)

[edit] Notes

This function is typically accessed through std::basic_istringstream::str(), std::basic_ostringstream::str(), or std::basic_stringstream::str().

[edit] Example

#include #include   int main() { int n;   std::istringstream in; // could also use in("1 2") in.rdbuf()->str("1 2"); // set the get area in >> n; std::cout << "after reading the first int from "1 2", the int is " << n << ", str() = "" << in.rdbuf()->str() << ""\n"; // or in.str()   std::ostringstream out("1 2"); out << 3; std::cout << "after writing the int '3' to output stream "1 2"" << ", str() = "" << out.str() << ""\n";   std::ostringstream ate("1 2", std::ios_base::ate); // C++11 ate << 3; std::cout << "after writing the int '3' to append stream "1 2"" << ", str() = "" << ate.str() << ""\n"; }

Output:

after reading the first int from "1 2", the int is 1, str() = "1 2" after writing the int '3' to output stream "1 2", str() = "3 2" after writing the int '3' to append stream "1 2", str() = "1 23"

[edit] Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit] See also

| | gets or sets the contents of underlying string device object (public member function of std::basic_stringstream<CharT,Traits,Allocator>) [edit] | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | obtains a view over the underlying character sequence (public member function) [edit] |