std::basic_filebuf

 

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basic_streambuf

basic_filebuf

basic_stringbuf

basic_spanbuf (C++23)

strstreambuf (C++98/26*)

basic_syncbuf (C++20)

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iostream_category (C++11)

io_errc (C++11)

 

std::basic_filebuf

公开成员函数

basic_filebuf::basic_filebuf

basic_filebuf::~basic_filebuf

basic_filebuf::operator= (C++11)

basic_filebuf::swap (C++11)

basic_filebuf::native_handle (C++26)

basic_filebuf::is_open

basic_filebuf::open

basic_filebuf::close

受保护的成员函数

basic_filebuf::showmanyc

basic_filebuf::underflow

basic_filebuf::uflow

basic_filebuf::pbackfail

basic_filebuf::overflow

basic_filebuf::setbuf

basic_filebuf::seekoff

basic_filebuf::seekpos

basic_filebuf::sync

basic_filebuf::imbue

非成员函数

swap(std::basic_filebuf) (C++11)

 

定义于头文件 <fstream>
template<     class CharT,     class Traits = std::char_traits<CharT> > class basic_filebuf : public std::basic_streambuf<CharT, Traits>

std::basic_filebuf 是 std::basic_streambuf 的一个特化，其关联字符序列是一个文件。输入序列和输出序列都与同一个文件关联，并且为这两个操作维护一个共享的文件位置。使用 std::basic_filebuf 读取和写入序列的限制与 std::FILE 相同。

函数 underflow() 和 overflow() / sync() 在文件与缓冲区的获取区和放置区之间执行实际的 I/O。当 CharT 不是 char 时，大多数实现将多字节字符存储在文件中，并使用 std::codecvt facet 执行宽字符/多字节字符转换。

提供了用于常见字符类型的几个 typedef

定义于头文件 <fstream>
类型	定义
std::filebuf	std::basic_filebuf<char>
std::wfilebuf	std::basic_filebuf<wchar_t>

成员类型

类型	定义
char_type	CharT
traits_type	Traits；如果 Traits::char_type 不是 CharT，则程序格式错误。
int_type	Traits::int_type
pos_type	Traits::pos_type，要求为 std::fpos<Traits::state_type>
off_type	Traits::off_type
native_handle_type(C++26)	实现定义类型，它是TriviallyCopyable且semiregular的

成员函数

公开成员函数
(构造函数)	构造一个 basic_filebuf 对象 (public member function)
operator= (C++11)	赋值一个 basic_filebuf 对象 (public member function)
swap (C++11)	交换两个 basic_filebuf 对象 (public member function)
native_handle (C++26)	返回底层实现定义的句柄 (public member function)
(析构函数) [virtual]	销毁一个 basic_filebuf 对象，如果文件已打开则关闭它 (virtual public member function)
is_open	检查关联文件是否打开 (public member function)
open	打开一个文件并将其配置为关联字符序列 (public member function)
close	刷新输出缓冲区并关闭关联文件 (public member function)
受保护的成员函数
showmanyc [virtual]	可选地提供可从文件中输入的字符数量 (virtual protected member function)
underflow [virtual]	从关联文件读取 (virtual protected member function)
uflow [virtual]	从关联文件读取并推进获取区中的下一指针 (virtual protected member function)
pbackfail [virtual]	回退输入序列以回推字符，不影响关联文件 (virtual protected member function)
overflow [virtual]	从放置区向关联文件写入字符 (virtual protected member function)
setbuf [virtual]	提供用户提供的缓冲区或将此文件缓冲区设为无缓冲 (virtual protected member function)
seekoff [virtual]	使用相对地址重新定位文件位置 (virtual protected member function)
seekpos [virtual]	使用绝对地址重新定位文件位置 (virtual protected member function)
sync [virtual]	从放置区向关联文件写入字符 (virtual protected member function)
imbue [virtual]	更改关联的区域设置 (virtual protected member function)

非成员函数

std::swap(std::basic_filebuf) (C++11)

特化 std::swap 算法 (function template)

继承自 std::basic_streambuf

成员类型

成员类型	定义
char_type	CharT
traits_type	Traits；如果 Traits::char_type 不是 CharT，则程序格式错误。
int_type	Traits::int_type
pos_type	Traits::pos_type
off_type	Traits::off_type

成员函数

(析构函数) [virtual]	销毁 basic_streambuf 对象 (virtual public member function of std::basic_streambuf<CharT,Traits>)
区域设置
pubimbue	更改关联的区域设置并调用 imbue() (public member function of std::basic_streambuf<CharT,Traits>)
getloc	获取关联区域设置的副本 (public member function of std::basic_streambuf<CharT,Traits>)
定位
pubsetbuf	调用 setbuf() (public member function of std::basic_streambuf<CharT,Traits>)
pubseekoff	调用 seekoff() (public member function of std::basic_streambuf<CharT,Traits>)
pubseekpos	调用 seekpos() (public member function of std::basic_streambuf<CharT,Traits>)
pubsync	调用 sync() (public member function of std::basic_streambuf<CharT,Traits>)
获取区
in_avail	获取获取区中立即可用的字符数 (public member function of std::basic_streambuf<CharT,Traits>)
snextc	推进输入序列，然后读取一个字符而不再次推进 (public member function of std::basic_streambuf<CharT,Traits>)
sbumpcstossc (C++17 中移除)	从输入序列中读取一个字符并推进序列 (public member function of std::basic_streambuf<CharT,Traits>)
sgetc	从输入序列中读取一个字符而不推进序列 (public member function of std::basic_streambuf<CharT,Traits>)
sgetn	调用 xsgetn() (public member function of std::basic_streambuf<CharT,Traits>)
放置区
sputc	将一个字符写入放置区并推进下一个指针 (public member function of std::basic_streambuf<CharT,Traits>)
sputn	调用 xsputn() (public member function of std::basic_streambuf<CharT,Traits>)
回放
sputbackc	将一个字符放回输入序列 (public member function of std::basic_streambuf<CharT,Traits>)
sungetc	将输入序列中的下一个指针后退一个位置 (public member function of std::basic_streambuf<CharT,Traits>)

受保护的成员函数

(构造函数)	构造 basic_streambuf 对象 (protected member function)
operator= (C++11)	替换 basic_streambuf 对象 (protected member function)
swap (C++11)	交换两个 basic_streambuf 对象 (protected member function)
区域设置
imbue [virtual]	响应关联区域设置的更改 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
定位
setbuf [virtual]	如果允许，用用户定义的数组替换缓冲区 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
seekoff [virtual]	使用相对寻址重新定位输入序列、输出序列或两者的下一个指针 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
seekpos [virtual]	使用绝对寻址重新定位输入序列、输出序列或两者的下一个指针 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
sync [virtual]	将缓冲区与关联的字符序列同步 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
获取区
showmanyc [virtual]	如果已知，获取关联输入序列中可用于输入的字符数 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
underflow [virtual]	从关联输入序列中读取字符到获取区 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
uflow [virtual]	从关联输入序列中读取字符到获取区并推进下一个指针 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
xsgetn [virtual]	从输入序列中读取多个字符 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
ebackgptregptr	返回获取区起始、当前字符和结尾的指针 (protected member function)
gbump	推进输入序列中的下一个指针 (protected member function)
setg	重新定位输入序列的起始、下一个和结束指针 (protected member function)
放置区
xsputn [virtual]	向输出序列写入多个字符 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
overflow [virtual]	从放置区向关联输出序列写入字符 (virtual protected member function of std::basic_streambuf<CharT,Traits>)
pbasepptrepptr	返回放置区起始、当前字符和结尾的指针 (protected member function)
pbump	推进输出序列的下一个指针 (protected member function)
setp	重新定位输出序列的起始、下一个和结束指针 (protected member function)
回放
pbackfail [virtual]	将一个字符放回输入序列，可能会修改输入序列 (virtual protected member function of std::basic_streambuf<CharT,Traits>)

注释

特性测试宏	值	标准	特性
__cpp_lib_fstream_native_handle	202306L	(C++26)	原生句柄支持

参阅

FILE	对象类型，能够保存控制 C I/O 流所需的所有信息 (typedef)