Difference between revisions of "cpp/io/basic ostream"

Latest revision as of 02:37, 7 December 2023

Defined in header `<ostream>`
template< class CharT, class Traits = std::char_traits<CharT> > class basic_ostream : virtual public std::basic_ios<CharT, Traits>

The class template basic_ostream provides support for high level output operations on character streams. The supported operations include formatted output (e.g. integer values) and unformatted output (e.g. raw characters and character arrays). This functionality is implemented in terms of the interface provided by the basic_streambuf class, accessed through the basic_ios base class. In typical implementations, basic_ostream has no non-inherited data members.

Inheritance diagram

Several typedefs for common character types are provided:

Defined in header `<ostream>`
Type	Definition
`std::ostream`	std::basic_ostream<char>
`std::wostream`	std::basic_ostream<wchar_t>

[edit] Global objects

Six global basic_ostream objects are provided by the standard library:

Defined in header `<iostream>`
coutwcout	writes to the standard C output stream stdout (global object)[edit]
cerrwcerr	writes to the standard C error stream stderr, unbuffered (global object)[edit]
clogwclog	writes to the standard C error stream stderr (global object)[edit]

[edit] Member types

Member type	Definition
`char_type`	`CharT`[edit]
`traits_type`	`Traits`; the program is ill-formed if `Traits::char_type` is not `CharT`.[edit]
`int_type`	`Traits::int_type`[edit]
`pos_type`	`Traits::pos_type`[edit]
`off_type`	`Traits::off_type`[edit]

[edit] Member functions

(constructor)	constructs the object (public member function) [edit]
(destructor) [virtual]	destructs the object (virtual public member function) [edit]
operator= (C++11)	move-assigns from another `basic_ostream` (protected member function) [edit]
Formatted output
operator<<	inserts formatted data (public member function) [edit]
Unformatted output
put	inserts a character (public member function) [edit]
write	inserts blocks of characters (public member function) [edit]
Positioning
tellp	returns the output position indicator (public member function) [edit]
seekp	sets the output position indicator (public member function) [edit]
Miscellaneous
flush	synchronizes with the underlying storage device (public member function) [edit]
swap (C++11)	swaps stream objects, except for the associated buffer (protected member function) [edit]

[edit] Member classes

sentry

implements basic logic for preparation of the stream for output operations
(public member class) [edit]

[edit] Non-member functions

operator<<(std::basic_ostream)	inserts character data or insert into rvalue stream (function template) [edit]
print(std::ostream) (C++23)	outputs formatted representation of the arguments (function template) [edit]
println(std::ostream) (C++23)	outputs formatted representation of the arguments with appended '\n' (function template) [edit]
vprint_unicode(std::ostream) (C++23)	performs Unicode aware output using type-erased argument representation (function) [edit]
vprint_nonunicode(std::ostream) (C++23)	outputs character data using type-erased argument representation (function) [edit]

Inherited from std::basic_ios

Member types

Member type	Definition
`char_type`	`CharT`
`traits_type`	`Traits`
`int_type`	`Traits::int_type`
`pos_type`	`Traits::pos_type`
`off_type`	`Traits::off_type`

Member functions

State functions
good	checks if no error has occurred i.e. I/O operations are available (public member function of `std::basic_ios<CharT,Traits>`) [edit]
eof	checks if end-of-file has been reached (public member function of `std::basic_ios<CharT,Traits>`) [edit]
fail	checks if an error has occurred (public member function of `std::basic_ios<CharT,Traits>`) [edit]
bad	checks if a non-recoverable error has occurred (public member function of `std::basic_ios<CharT,Traits>`) [edit]
operator!	checks if an error has occurred (synonym of fail()) (public member function of `std::basic_ios<CharT,Traits>`) [edit]
operator bool	checks if no error has occurred (synonym of `!`fail()) (public member function of `std::basic_ios<CharT,Traits>`) [edit]
rdstate	returns state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
setstate	sets state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
clear	modifies state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
Formatting
copyfmt	copies formatting information (public member function of `std::basic_ios<CharT,Traits>`) [edit]
fill	manages the fill character (public member function of `std::basic_ios<CharT,Traits>`) [edit]
Miscellaneous
exceptions	manages exception mask (public member function of `std::basic_ios<CharT,Traits>`) [edit]
imbue	sets the locale (public member function of `std::basic_ios<CharT,Traits>`) [edit]
rdbuf	manages associated stream buffer (public member function of `std::basic_ios<CharT,Traits>`) [edit]
tie	manages tied stream (public member function of `std::basic_ios<CharT,Traits>`) [edit]
narrow	narrows characters (public member function of `std::basic_ios<CharT,Traits>`) [edit]
widen	widens characters (public member function of `std::basic_ios<CharT,Traits>`) [edit]

Inherited from std::ios_base

Member functions

Formatting
flags	manages format flags (public member function of `std::ios_base`) [edit]
setf	sets specific format flag (public member function of `std::ios_base`) [edit]
unsetf	clears specific format flag (public member function of `std::ios_base`) [edit]
precision	manages decimal precision of floating point operations (public member function of `std::ios_base`) [edit]
width	manages field width (public member function of `std::ios_base`) [edit]
Locales
imbue	sets locale (public member function of `std::ios_base`) [edit]
getloc	returns current locale (public member function of `std::ios_base`) [edit]
Internal extensible array
xalloc [static]	returns a program-wide unique integer that is safe to use as index to `pword()` and `iword()` (public static member function of `std::ios_base`) [edit]
iword	resizes the private storage if necessary and access to the long element at the given index (public member function of `std::ios_base`) [edit]
pword	resizes the private storage if necessary and access to the void* element at the given index (public member function of `std::ios_base`) [edit]
Miscellaneous
register_callback	registers event callback function (public member function of `std::ios_base`) [edit]
sync_with_stdio [static]	sets whether C++ and C I/O libraries are interoperable (public static member function of `std::ios_base`) [edit]
Member classes
failure	stream exception (public member class of `std::ios_base`) [edit]
Init	initializes standard stream objects (public member class of `std::ios_base`) [edit]

Member types and constants

Type Explanation

openmode

stream open mode type

The following constants are also defined:

Constant	Explanation[edit]
`app`	seek to the end of stream before each write[edit]
`binary`	open in binary mode[edit]
`in`	open for reading[edit]
`out`	open for writing[edit]
`trunc`	discard the contents of the stream when opening[edit]
`ate`	seek to the end of stream immediately after open[edit]
`noreplace` (C++23)	open in exclusive mode[edit]

(typedef) [edit]

fmtflags

formatting flags type

The following constants are also defined:

Constant	Explanation[edit]
`dec`	use decimal base for integer I/O: see std::dec[edit]
`oct`	use octal base for integer I/O: see std::oct[edit]
`hex`	use hexadecimal base for integer I/O: see std::hex[edit]
`basefield`	dec \| oct \| hex. Useful for masking operations[edit]
`left`	left adjustment (adds fill characters to the right): see std::left[edit]
`right`	right adjustment (adds fill characters to the left): see std::right[edit]
`internal`	internal adjustment (adds fill characters to the internal designated point): see std::internal[edit]
`adjustfield`	left \| right \| internal. Useful for masking operations[edit]
`scientific`	generate floating point types using scientific notation, or hex notation if combined with fixed: see std::scientific[edit]
`fixed`	generate floating point types using fixed notation, or hex notation if combined with scientific: see std::fixed[edit]
`floatfield`	scientific \| fixed. Useful for masking operations[edit]
`boolalpha`	insert and extract bool type in alphanumeric format: see std::boolalpha[edit]
`showbase`	generate a prefix indicating the numeric base for integer output, require the currency indicator in monetary I/O: see std::showbase[edit]
`showpoint`	generate a decimal-point character unconditionally for floating-point number output: see std::showpoint[edit]
`showpos`	generate a + character for non-negative numeric output: see std::showpos[edit]
`skipws`	skip leading whitespace before certain input operations: see std::skipws[edit]
`unitbuf`	flush the output after each output operation: see std::unitbuf[edit]
`uppercase`	replace certain lowercase letters with their uppercase equivalents in certain output operations: see std::uppercase[edit]

(typedef) [edit]

iostate

state of the stream type

The following constants are also defined:

Constant	Explanation[edit]
`goodbit`	no error[edit]
`badbit`	irrecoverable stream error[edit]
`failbit`	input/output operation failed (formatting or extraction error)[edit]
`eofbit`	associated input sequence has reached end-of-file[edit]

(typedef) [edit]

seekdir

seeking direction type

The following constants are also defined:

Constant	Explanation[edit]
`beg`	the beginning of a stream[edit]
`end`	the ending of a stream[edit]
`cur`	the current position of stream position indicator[edit]

(typedef) [edit]

event

specifies event type
(enum) [edit]

event_callback

callback function type
(typedef) [edit]

@@ Line 1: / Line 1: @@
 {{cpp/title|basic_ostream}}
-{{cpp/io/basic_ostream/sidebar}}
+{{cpp/io/basic_ostream/navbar}}
-{{ddcl | header=ostream |
+{{ddcl|header=ostream|1=
 template<
      class CharT,
-     class Traits {{=}} std::char_traits<CharT>
+     class Traits = std::char_traits<CharT>
-> class basic_ostream;
+> class basic_ostream : virtual public std::basic_ios<CharT, Traits>
 }}
-<!--
+The class template {{tt|basic_ostream}} provides support for high level output operations on character streams. The supported operations include formatted output (e.g. integer values) and unformatted output (e.g. raw characters and character arrays). This functionality is implemented in terms of the interface provided by the {{tt|basic_streambuf}} class, accessed through the {{tt|basic_ios}} base class. In typical implementations, {{tt|basic_ostream}} has no non-inherited data members.
-<graphviz dot>
-digraph inheritance {
-    rankdir=LR
-    graph [dpi="65", label="Inheritance diagram"]
-    node [shape = box, fontsize=14, width=1.6, height=0.5];
-    base [label = "ios_base"];
+{{inheritance diagram/std-basic_ostream}}
-    ios [label = <basic_ios<br/><font color="#808080">&lt;charT, Traits&gt;</font>>];
-    ost [label = <basic_ostream<br/><font color="#808080">&lt;charT, Traits&gt;</font>>, style=filled];
-    base -> ios;
-    ios -> ost;
-}
-</graphviz>
--->
-The class template {{tt|basic_ostream}} provides support for output operations on streams. It inherits {{rlpt|ios_base}}, {{rlpt|basic_ios}} classes.
-Two specializations for common character types are also defined:
+{{cpp/basic char typedefs|ostream}}
-{{tdcl list begin}}
+===Global objects===
-{{tdcl list header | ostream}}
+Six global {{tt|basic_ostream}} objects are provided by the standard library:
-{{tdcl list hitem | Type | Definition}}
+{{dsc begin}}
-{{tdcl list item | {{tt|ostream}} | {{cpp|basic_ostream<char>}}}}
+{{dsc header|iostream}}
-{{tdcl list item | {{tt|wostream}} | {{cpp|basic_ostream<wchar_t>}}}}
+{{dsc inc|cpp/io/dsc cout}}
-{{tdcl list end}}
+{{dsc inc|cpp/io/dsc cerr}}
+{{dsc inc|cpp/io/dsc clog}}
+{{dsc end}}
-Also several objects are defined in {{tt|<iostream>}} header to provide access to the standard output ({{cpp|stdout}}), the standard error ({{cpp|stderr}}) and standard log ({{cpp|stdlog}}) streams:
+{{cpp/io/member types}}
-<source lang="cpp">
+===Member functions===
-extern ostream cout; //stdout
+{{dsc begin}}
-extern ostream cerr; //stderr
+{{dsc inc|cpp/io/basic_ostream/dsc constructor}}
-extern ostream clog; //stdlog
+{{dsc inc|cpp/io/basic_ostream/dsc destructor}}
+{{dsc inc|cpp/io/basic_ostream/dsc operator{{=}}}}
-extern ostream wcout; //stdout (wide character)
-extern ostream wcerr; //stderr (wide character)
-extern ostream wclog; //stdlog (wide character)
-</source>
-{{tdcl list begin}}
+{{dsc h2|Formatted output}}
-{{tdcl list h1 | Member types}}
+{{dsc inc|cpp/io/basic_ostream/dsc operator_ltlt}}
-{{tdcl list hitem | Member type | Definition}}
-{{tdcl list template | cpp/io/tdcl list char_type}}
-{{tdcl list template | cpp/io/tdcl list traits_type}}
-{{tdcl list template | cpp/io/tdcl list int_type}}
-{{tdcl list template | cpp/io/tdcl list pos_type}}
-{{tdcl list template | cpp/io/tdcl list off_type}}
-{{tdcl list end}}
-{{dcl list begin}}
+{{dsc h2|Unformatted output}}
-{{dcl list h1 | Member functions }}
+{{dsc inc|cpp/io/basic_ostream/dsc put}}
-{{dcl list template | cpp/io/basic_ostream/dcl list basic_ostream}}
+{{dsc inc|cpp/io/basic_ostream/dsc write}}
-{{dcl list template | cpp/io/basic_ostream/dcl list ~basic_ostream}}
-{{dcl list h2 | Formatted input }}
+{{dsc h2|Positioning}}
-{{dcl list template | cpp/io/basic_ostream/dcl list operator_ltlt}}
+{{dsc inc|cpp/io/basic_ostream/dsc tellp}}
+{{dsc inc|cpp/io/basic_ostream/dsc seekp}}
-{{dcl list h2 | Unformatted input }}
+{{dsc h2|Miscellaneous}}
-{{dcl list template | cpp/io/basic_ostream/dcl list put}}
+{{dsc inc|cpp/io/basic_ostream/dsc flush}}
-{{dcl list template | cpp/io/basic_ostream/dcl list write}}
+{{dsc inc|cpp/io/basic_ostream/dsc swap}}
+{{dsc end}}
-{{dcl list h2 | Positioning }}
+===Member classes===
-{{dcl list template | cpp/io/basic_ostream/dcl list tellp}}
+{{dsc begin}}
-{{dcl list template | cpp/io/basic_ostream/dcl list seekp}}
+{{dsc inc|cpp/io/basic_ostream/dsc sentry}}
+{{dsc end}}
-{{dcl list h2 | Miscellaneous }}
+===Non-member functions===
-{{dcl list template | cpp/io/basic_ostream/dcl list flush}}
+{{dsc begin}}
+{{dsc inc|cpp/io/basic_ostream/dsc operator_ltlt2}}
-{{dcl list h1 | Member classes }}
+{{dsc inc|cpp/io/basic_ostream/dsc print}}
-{{dcl list template | cpp/io/basic_ostream/dcl list sentry}}
+{{dsc inc|cpp/io/basic_ostream/dsc println}}
-{{dcl list end}}
+{{dsc inc|cpp/io/basic_ostream/dsc vprint_unicode}}
+{{dsc inc|cpp/io/basic_ostream/dsc vprint_nonunicode}}
+{{dsc end}}
 {{cpp/io/basic_ios/inherit}}
 {{cpp/io/ios_base/inherit}}
+{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

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Difference between revisions of "cpp/io/basic ostream"

Latest revision as of 02:37, 7 December 2023

Contents

[edit] Global objects

[edit] Member types

[edit] Member functions

Formatted output

Unformatted output

Positioning

Miscellaneous

[edit] Member classes

[edit] Non-member functions

Inherited from std::basic_ios

Member types

Member functions

State functions

Formatting

Miscellaneous

Inherited from std::ios_base

Member functions

Formatting

Locales

Internal extensible array

Miscellaneous

Member classes

Member types and constants

Navigation

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