FreeBSD Manual Pages
std::basic_...ic_stringbuf(3) C++ Standard Libarystd::basic_...ic_stringbuf(3) NAME std::basic_stringbuf::basic_stringbuf - std::basic_stringbuf::ba- sic_stringbuf Synopsis explicit basic_stringbuf( std::ios_base::openmode which = std::ios_base::in | (until C++11) std::ios_base::out ); explicit basic_stringbuf( std::ios_base::openmode which ); (since C++11) basic_stringbuf() : basic_stringbuf( std::ios_base::in | std::ios_base::out (2) (since C++11) ) {} explicit basic_stringbuf( const std::basic_string<CharT, Traits, Allocator>& s, (3) std::ios_base::openmode which = std::ios_base::in | std::ios_base::out ); explicit basic_stringbuf( std::basic_string<CharT, Traits, Allocator>&& s, std::ios_base::openmode which = (4) (since C++20) std::ios_base::in | std::ios_base::out ); basic_stringbuf( std::ios_base::openmode which, const (5) (since C++20) Allocator& a ); explicit basic_stringbuf( const Allocator& a ) : basic_stringbuf( std::ios_base::in | (6) (since C++20) std::ios_base::out, a ) {} template< class SAlloc > explicit basic_stringbuf( const std::basic_string<CharT, Traits, SAlloc>& s, (7) (since C++20) std::ios_base::openmode which = std::ios_base::in | std::ios_base::out ); (1) template< class SAlloc > basic_stringbuf( const std::basic_string<CharT, Traits, SAlloc>& s, (8) (since C++20) std::ios_base::openmode which, const Allocator& a ); template< class SAlloc > basic_stringbuf( const std::basic_string<CharT, Traits, SAlloc>& s, (9) (since C++20) const Allocator& a ) : basic_stringbuf( s, std::ios_base::in | std::ios_base::out, a ) {} template< class StringViewLike > explicit basic_stringbuf( const StringViewLike& t, std::ios_base::openmode which = (10) (since C++26) std::ios_base::in | std::ios_base::out ); template< class StringViewLike > basic_stringbuf( const StringViewLike& t, (11) (since C++26) std::ios_base::openmode which, const Allocator& a ); template< class StringViewLike > basic_stringbuf( const StringViewLike& t, const Allocator& a (12) (since C++26) ); basic_stringbuf( basic_stringbuf&& rhs ); (13) (since C++11) basic_stringbuf( basic_stringbuf&& rhs, const Allocator& a ); (14) (since C++20) basic_stringbuf( const basic_stringbuf& rhs ) = delete; (15) (since C++11) The std::basic_streambuf base and the exposition-only data members buf and mode are initialized as follows. After initializing these subobjects, overloads (3-12) initialize the input and output sequences as if by calling init_buf_ptrs(). Overload std::basic_streambuf buf mode base (1) which implementation-defined std::ios_base::in | (2) (see below) std::ios_base::out (3) s (4) std::move(s) which (5) a std::ios_base::in | (6) default-initialized std::ios_base::out (7) s which (8) {s, a} std::ios_base::in | (9) std::ios_base::out (10) {sv, Allocator()} which (11) {sv, a} std::ios_base::in | (12) std::ios_base::out (13) rhs std::move(rhs).str() (14) (copy constructed) {std::move(rhs).str(), rhs.mode a} 1,2) Overload (1) (until C++11) (2) (since C++11) is the default constructor. It is implementation-de- fined whether the sequence pointers (eback(), gptr(), egptr(), pbase(), pptr(), epptr()) are initialized to null pointers. 5,6) When the construction is complete, str.empty() is true. 7) This overload participates in overload resolution only if std::is_same_v<SAlloc, Allocator> is false. 10-12) Implicitly converts t to a string view sv as if by std::basic_string_view<CharT, Traits> sv = t;, then it is used as above in the table. These overloads participate in overload resolution only if std::is_convertible_v<const StringViewLike&, std::basic_string_view<CharT, Traits>> is true. 13,14) Overload (13) is the move constructor. It is implementation- defined whether the six sequence pointers in *this obtain the values which rhs had. When the construction is complete, rhs is empty but usable, and * Let rhs_p refer to the state of rhs just prior to this construc- tion, the following expressions will evaluate to true: * str() == rhs_p.str() * getloc() == rhs_p.getloc() * gptr() - eback() == rhs_p.gptr() - rhs_p.eback() * egptr() - eback() == rhs_p.egptr() - rhs_p.eback() * pptr() - pbase() == rhs_p.pptr() - rhs_p.pbase() * epptr() - pbase() == rhs_p.epptr() - rhs_p.pbase() * Let rhs_a refer to the state of rhs just after this construc- tion, the following expressions will evaluate to true: * !eback() || eback() != rhs_a.eback() * !gptr() || gptr() != rhs_a.gptr() * !egptr() || egptr() != rhs_a.egptr() * !pbase() || pbase() != rhs_a.pbase() * !pptr() || pptr() != rhs_a.pptr() * !epptr() || epptr() != rhs_a.epptr() 15) The copy constructor is deleted; std::basic_stringbuf is not CopyConstructible. Parameters s - a std::basic_string used to initialize the buffer t - an object (convertible to std::basic_string_view) used to initialize the buffer a - another allocator used to construct the internal std::ba- sic_string rhs - another basic_stringbuf specifies stream open mode. It is bitmask type, the follow- ing constants are defined: Constant Explanation app seek to the end of stream before each write which - binary open in binary mode in open for reading out open for writing trunc discard the contents of the stream when opening ate seek to the end of stream immediately af- ter open noreplace (C++23) open in exclusive mode Notes Typically called by the constructor of std::basic_stringstream. The level of support for the open modes other than std::ios_base::in and std::ios_base::out varies among implementations. C++11 explicitly specifies the support for std::ios_base::ate in str() and in this constructor, but std::ios_base::app, std::ios_base::trunc, and std::ios_base::binary have different effects on different implementations. Feature-test macro Value Std Fea- ture __cpp_lib_sstream_from_string_view 202306L (C++26) Interfacing string streams with std::string_view Example Demonstrates calling the constructor of std::basic_stringbuf di- rectly: // Run this code #include <iostream> #include <sstream> int main() { // default constructor (mode = in | out) std::stringbuf buf1; buf1.sputc('1'); std::cout << &buf1 << '\n'; // string constructor in at-end mode (C++11) std::stringbuf buf2("test", std::ios_base::in | std::ios_base::out | std::ios_base::ate); buf2.sputc('1'); std::cout << &buf2 << '\n'; // append mode test (results differ among compilers) std::stringbuf buf3("test", std::ios_base::in | std::ios_base::out | std::ios_base::app); buf3.sputc('1'); buf3.pubseekpos(1); buf3.sputc('2'); std::cout << &buf3 << '\n'; } Output: 1 test1 est12 (Sun Studio) 2st1 (GCC) Defect reports The following behavior-changing defect reports were applied retroac- tively to previously published C++ standards. DR Applied to Behavior as published Correct behavior 1. overload (1) allocated no array object 1. removed the LWG 432 C++98 2. overload (3) did not specify how the limi- tation input 2. specified and output sequences are initialized overload (3) set epptr() to point one past LWG 562 C++98 the last underlying epptr() can be set character if bool(which & be- yond that position std::ios_base::out) == true P0935R0 C++11 the default constructor was explicit made implicit See also constructs the string stream constructor (public member function of std::basic_stringstream<CharT,Traits,Allocator>) http://cppreference.com 2024.06.10 std::basic_...ic_stringbuf(3)
NAME | Synopsis | Parameters | Notes | Example | Output: | See also
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::stringbuf::basic_stringbuf&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>