.TH "std::ios_base" 3cxx "Fri May 28 2021" "libstdc++" \" -*- nroff -*-
.ad l
.nh
.SH NAME
std::ios_base \- The base of the I/O class hierarchy\&.  

.SH SYNOPSIS
.br
.PP
.PP
Inherited by \fBstd::basic_ios< char, _Traits >\fP, and \fBstd::basic_ios< _CharT, _Traits >\fP\&.
.SS "Classes"

.in +1c
.ti -1c
.RI "class \fBfailure\fP"
.br
.RI "These are thrown to indicate problems with io\&. "
.in -1c
.SS "Public Types"

.in +1c
.ti -1c
.RI "typedef int io_state \fB_GLIBCXX_DEPRECATED_SUGGEST\fP('std::iostate')"
.br
.ti -1c
.RI "typedef int open_mode \fB_GLIBCXX_DEPRECATED_SUGGEST\fP('std::openmode')"
.br
.ti -1c
.RI "typedef int seek_dir \fB_GLIBCXX_DEPRECATED_SUGGEST\fP('std::seekdir')"
.br
.ti -1c
.RI "typedef \fBstd::streamoff\fP \fBstreamoff\fP \fB_GLIBCXX_DEPRECATED_SUGGEST\fP('std::streamoff')"
.br
.ti -1c
.RI "typedef \fBstd::streampos\fP \fBstreampos\fP \fB_GLIBCXX_DEPRECATED_SUGGEST\fP('std::streampos')"
.br
.ti -1c
.RI "enum \fBevent\fP { \fBerase_event\fP, \fBimbue_event\fP, \fBcopyfmt_event\fP }"
.br
.RI "The set of events that may be passed to an event callback\&. "
.ti -1c
.RI "typedef void(* \fBevent_callback\fP) (\fBevent\fP __e, \fBios_base\fP &__b, int __i)"
.br
.RI "The type of an event callback function\&. "
.ti -1c
.RI "typedef _Ios_Fmtflags \fBfmtflags\fP"
.br
.RI "This is a bitmask type\&. "
.ti -1c
.RI "typedef _Ios_Iostate \fBiostate\fP"
.br
.RI "This is a bitmask type\&. "
.ti -1c
.RI "typedef _Ios_Openmode \fBopenmode\fP"
.br
.RI "This is a bitmask type\&. "
.ti -1c
.RI "typedef _Ios_Seekdir \fBseekdir\fP"
.br
.RI "This is an enumerated type\&. "
.in -1c
.SS "Public Member Functions"

.in +1c
.ti -1c
.RI "\fBios_base\fP (const \fBios_base\fP &)=delete"
.br
.ti -1c
.RI "virtual \fB~ios_base\fP ()"
.br
.ti -1c
.RI "const \fBlocale\fP & \fB_M_getloc\fP () const"
.br
.RI "Locale access\&. "
.ti -1c
.RI "\fBfmtflags\fP \fBflags\fP () const"
.br
.RI "Access to format flags\&. "
.ti -1c
.RI "\fBfmtflags\fP \fBflags\fP (\fBfmtflags\fP __fmtfl)"
.br
.RI "Setting new format flags all at once\&. "
.ti -1c
.RI "\fBlocale\fP \fBgetloc\fP () const"
.br
.RI "Locale access\&. "
.ti -1c
.RI "\fBlocale\fP \fBimbue\fP (const \fBlocale\fP &__loc)  throw ()"
.br
.RI "Setting a new locale\&. "
.ti -1c
.RI "long & \fBiword\fP (int __ix)"
.br
.RI "Access to integer array\&. "
.ti -1c
.RI "\fBios_base\fP & \fBoperator=\fP (const \fBios_base\fP &)=delete"
.br
.ti -1c
.RI "\fBstreamsize\fP \fBprecision\fP () const"
.br
.RI "Flags access\&. "
.ti -1c
.RI "\fBstreamsize\fP \fBprecision\fP (\fBstreamsize\fP __prec)"
.br
.RI "Changing flags\&. "
.ti -1c
.RI "void *& \fBpword\fP (int __ix)"
.br
.RI "Access to void pointer array\&. "
.ti -1c
.RI "void \fBregister_callback\fP (\fBevent_callback\fP __fn, int __index)"
.br
.RI "Add the callback __fn with parameter __index\&. "
.ti -1c
.RI "\fBfmtflags\fP \fBsetf\fP (\fBfmtflags\fP __fmtfl)"
.br
.RI "Setting new format flags\&. "
.ti -1c
.RI "\fBfmtflags\fP \fBsetf\fP (\fBfmtflags\fP __fmtfl, \fBfmtflags\fP __mask)"
.br
.RI "Setting new format flags\&. "
.ti -1c
.RI "void \fBunsetf\fP (\fBfmtflags\fP __mask)"
.br
.RI "Clearing format flags\&. "
.ti -1c
.RI "\fBstreamsize\fP \fBwidth\fP () const"
.br
.RI "Flags access\&. "
.ti -1c
.RI "\fBstreamsize\fP \fBwidth\fP (\fBstreamsize\fP __wide)"
.br
.RI "Changing flags\&. "
.in -1c
.SS "Static Public Member Functions"

.in +1c
.ti -1c
.RI "static bool \fBsync_with_stdio\fP (bool __sync=true)"
.br
.RI "Interaction with the standard C I/O objects\&. "
.ti -1c
.RI "static int \fBxalloc\fP ()  throw ()"
.br
.RI "Access to unique indices\&. "
.in -1c
.SS "Static Public Attributes"

.in +1c
.ti -1c
.RI "static const \fBfmtflags\fP \fBadjustfield\fP"
.br
.RI "A mask of left|right|internal\&. Useful for the 2-arg form of \fCsetf\fP\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBapp\fP"
.br
.RI "Seek to end before each write\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBate\fP"
.br
.RI "Open and seek to end immediately after opening\&. "
.ti -1c
.RI "static const \fBiostate\fP \fBbadbit\fP"
.br
.RI "Indicates a loss of integrity in an input or output sequence (such as an irrecoverable read error from a file)\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBbasefield\fP"
.br
.RI "A mask of dec|oct|hex\&. Useful for the 2-arg form of \fCsetf\fP\&. "
.ti -1c
.RI "static const \fBseekdir\fP \fBbeg\fP"
.br
.RI "Request a seek relative to the beginning of the stream\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBbinary\fP"
.br
.RI "Perform input and output in binary mode (as opposed to text mode)\&. This is probably not what you think it is; see https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBboolalpha\fP"
.br
.RI "Insert/extract \fCbool\fP in alphabetic rather than numeric format\&. "
.ti -1c
.RI "static const \fBseekdir\fP \fBcur\fP"
.br
.RI "Request a seek relative to the current position within the sequence\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBdec\fP"
.br
.RI "Converts integer input or generates integer output in decimal base\&. "
.ti -1c
.RI "static const \fBseekdir\fP \fBend\fP"
.br
.RI "Request a seek relative to the current end of the sequence\&. "
.ti -1c
.RI "static const \fBiostate\fP \fBeofbit\fP"
.br
.RI "Indicates that an input operation reached the end of an input sequence\&. "
.ti -1c
.RI "static const \fBiostate\fP \fBfailbit\fP"
.br
.RI "Indicates that an input operation failed to read the expected characters, or that an output operation failed to generate the desired characters\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBfixed\fP"
.br
.RI "Generate floating-point output in fixed-point notation\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBfloatfield\fP"
.br
.RI "A mask of scientific|fixed\&. Useful for the 2-arg form of \fCsetf\fP\&. "
.ti -1c
.RI "static const \fBiostate\fP \fBgoodbit\fP"
.br
.RI "Indicates all is well\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBhex\fP"
.br
.RI "Converts integer input or generates integer output in hexadecimal base\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBin\fP"
.br
.RI "Open for input\&. Default for \fCifstream\fP and fstream\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBinternal\fP"
.br
.RI "Adds fill characters at a designated internal point in certain generated output, or identical to \fCright\fP if no such point is designated\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBleft\fP"
.br
.RI "Adds fill characters on the right (final positions) of certain generated output\&. (I\&.e\&., the thing you print is flush left\&.) "
.ti -1c
.RI "static const \fBfmtflags\fP \fBoct\fP"
.br
.RI "Converts integer input or generates integer output in octal base\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBout\fP"
.br
.RI "Open for output\&. Default for \fCofstream\fP and fstream\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBright\fP"
.br
.RI "Adds fill characters on the left (initial positions) of certain generated output\&. (I\&.e\&., the thing you print is flush right\&.) "
.ti -1c
.RI "static const \fBfmtflags\fP \fBscientific\fP"
.br
.RI "Generates floating-point output in scientific notation\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBshowbase\fP"
.br
.RI "Generates a prefix indicating the numeric base of generated integer output\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBshowpoint\fP"
.br
.RI "Generates a decimal-point character unconditionally in generated floating-point output\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBshowpos\fP"
.br
.RI "Generates a + sign in non-negative generated numeric output\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBskipws\fP"
.br
.RI "Skips leading white space before certain input operations\&. "
.ti -1c
.RI "static const \fBopenmode\fP \fBtrunc\fP"
.br
.RI "Truncate an existing stream when opening\&. Default for \fCofstream\fP\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBunitbuf\fP"
.br
.RI "Flushes output after each output operation\&. "
.ti -1c
.RI "static const \fBfmtflags\fP \fBuppercase\fP"
.br
.RI "Replaces certain lowercase letters with their uppercase equivalents in generated output\&. "
.in -1c
.SS "Protected Types"

.in +1c
.ti -1c
.RI "enum { \fB_S_local_word_size\fP }"
.br
.in -1c
.SS "Protected Member Functions"

.in +1c
.ti -1c
.RI "void \fB_M_call_callbacks\fP (\fBevent\fP __ev)  throw ()"
.br
.ti -1c
.RI "void \fB_M_dispose_callbacks\fP (void)  throw ()"
.br
.ti -1c
.RI "_Words & \fB_M_grow_words\fP (int __index, bool __iword)"
.br
.ti -1c
.RI "void \fB_M_init\fP ()  throw ()"
.br
.ti -1c
.RI "void \fB_M_move\fP (\fBios_base\fP &) noexcept"
.br
.ti -1c
.RI "void \fB_M_swap\fP (\fBios_base\fP &__rhs) noexcept"
.br
.in -1c
.SS "Protected Attributes"

.in +1c
.ti -1c
.RI "_Callback_list * \fB_M_callbacks\fP"
.br
.ti -1c
.RI "\fBiostate\fP \fB_M_exception\fP"
.br
.ti -1c
.RI "\fBfmtflags\fP \fB_M_flags\fP"
.br
.ti -1c
.RI "\fBlocale\fP \fB_M_ios_locale\fP"
.br
.ti -1c
.RI "_Words \fB_M_local_word\fP [_S_local_word_size]"
.br
.ti -1c
.RI "\fBstreamsize\fP \fB_M_precision\fP"
.br
.ti -1c
.RI "\fBiostate\fP \fB_M_streambuf_state\fP"
.br
.ti -1c
.RI "\fBstreamsize\fP \fB_M_width\fP"
.br
.ti -1c
.RI "_Words * \fB_M_word\fP"
.br
.ti -1c
.RI "int \fB_M_word_size\fP"
.br
.ti -1c
.RI "_Words \fB_M_word_zero\fP"
.br
.in -1c
.SH "Detailed Description"
.PP 
The base of the I/O class hierarchy\&. 

This class defines everything that can be defined about I/O that does not depend on the type of characters being input or output\&. Most people will only see \fCios_base\fP when they need to specify the full name of the various I/O flags (e\&.g\&., the openmodes)\&. 
.PP
Definition at line 228 of file ios_base\&.h\&.
.SH "Member Typedef Documentation"
.PP 
.SS "typedef void(* std::ios_base::event_callback) (\fBevent\fP __e, \fBios_base\fP &__b, int __i)"

.PP
The type of an event callback function\&. 
.PP
\fBParameters\fP
.RS 4
\fI__e\fP One of the members of the event enum\&. 
.br
\fI__b\fP Reference to the ios_base object\&. 
.br
\fI__i\fP The integer provided when the callback was registered\&.
.RE
.PP
Event callbacks are user defined functions that get called during several ios_base and basic_ios functions, specifically imbue(), copyfmt(), and ~ios()\&. 
.PP
Definition at line 511 of file ios_base\&.h\&.
.SS "typedef _Ios_Fmtflags std::ios_base::fmtflags"

.PP
This is a bitmask type\&. \fC\fI_Ios_Fmtflags\fP is\fP implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen\&. Defined objects of type fmtflags are:
.IP "\(bu" 2
boolalpha
.IP "\(bu" 2
dec
.IP "\(bu" 2
fixed
.IP "\(bu" 2
hex
.IP "\(bu" 2
internal
.IP "\(bu" 2
left
.IP "\(bu" 2
oct
.IP "\(bu" 2
right
.IP "\(bu" 2
scientific
.IP "\(bu" 2
showbase
.IP "\(bu" 2
showpoint
.IP "\(bu" 2
showpos
.IP "\(bu" 2
skipws
.IP "\(bu" 2
unitbuf
.IP "\(bu" 2
uppercase
.IP "\(bu" 2
adjustfield
.IP "\(bu" 2
basefield
.IP "\(bu" 2
floatfield 
.PP

.PP
Definition at line 323 of file ios_base\&.h\&.
.SS "typedef _Ios_Iostate std::ios_base::iostate"

.PP
This is a bitmask type\&. \fC\fI_Ios_Iostate\fP is\fP implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen\&. Defined objects of type iostate are:
.IP "\(bu" 2
badbit
.IP "\(bu" 2
eofbit
.IP "\(bu" 2
failbit
.IP "\(bu" 2
goodbit 
.PP

.PP
Definition at line 398 of file ios_base\&.h\&.
.SS "typedef _Ios_Openmode std::ios_base::openmode"

.PP
This is a bitmask type\&. \fC\fI_Ios_Openmode\fP is\fP implementation-defined, but it is valid to perform bitwise operations on these values and expect the Right Thing to happen\&. Defined objects of type openmode are:
.IP "\(bu" 2
app
.IP "\(bu" 2
ate
.IP "\(bu" 2
binary
.IP "\(bu" 2
in
.IP "\(bu" 2
out
.IP "\(bu" 2
trunc 
.PP

.PP
Definition at line 429 of file ios_base\&.h\&.
.SS "typedef _Ios_Seekdir std::ios_base::seekdir"

.PP
This is an enumerated type\&. \fC\fI_Ios_Seekdir\fP is\fP implementation-defined\&. Defined values of type seekdir are:
.IP "\(bu" 2
beg
.IP "\(bu" 2
cur, equivalent to \fCSEEK_CUR\fP in the C standard library\&.
.IP "\(bu" 2
end, equivalent to \fCSEEK_END\fP in the C standard library\&. 
.PP

.PP
Definition at line 461 of file ios_base\&.h\&.
.SH "Member Enumeration Documentation"
.PP 
.SS "enum \fBstd::ios_base::event\fP"

.PP
The set of events that may be passed to an event callback\&. erase_event is used during ~ios() and copyfmt()\&. imbue_event is used during imbue()\&. copyfmt_event is used during copyfmt()\&. 
.PP
Definition at line 494 of file ios_base\&.h\&.
.SH "Constructor & Destructor Documentation"
.PP 
.SS "virtual std::ios_base::~ios_base ()\fC [virtual]\fP"
Invokes each callback with erase_event\&. Destroys local storage\&.
.PP
Note that the ios_base object for the standard streams never gets destroyed\&. As a result, any callbacks registered with the standard streams will not get invoked with erase_event (unless copyfmt is used)\&. 
.SH "Member Function Documentation"
.PP 
.SS "const \fBlocale\fP& std::ios_base::_M_getloc () const\fC [inline]\fP"

.PP
Locale access\&. 
.PP
\fBReturns\fP
.RS 4
A reference to the current locale\&.
.RE
.PP
Like getloc above, but returns a reference instead of generating a copy\&. 
.PP
Definition at line 786 of file ios_base\&.h\&.
.PP
Referenced by std::money_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_date(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_time(), std::time_get< _CharT, _InIter >::do_get_weekday(), std::num_put< _CharT, _OutIter >::do_put(), std::time_put< _CharT, _OutIter >::do_put(), std::time_get< _CharT, _InIter >::get(), and std::time_put< _CharT, _OutIter >::put()\&.
.SS "\fBfmtflags\fP std::ios_base::flags () const\fC [inline]\fP"

.PP
Access to format flags\&. 
.PP
\fBReturns\fP
.RS 4
The format control flags for both input and output\&. 
.RE
.PP

.PP
Definition at line 631 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(), std::gamma_distribution< double >::operator()(), std::operator<<(), std::operator>>(), and std::__detail::operator>>()\&.
.SS "\fBfmtflags\fP std::ios_base::flags (\fBfmtflags\fP __fmtfl)\fC [inline]\fP"

.PP
Setting new format flags all at once\&. 
.PP
\fBParameters\fP
.RS 4
\fI__fmtfl\fP The new flags to set\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous format control flags\&.
.RE
.PP
This function overwrites all the format flags with \fI__fmtfl\fP\&. 
.PP
Definition at line 642 of file ios_base\&.h\&.
.SS "\fBlocale\fP std::ios_base::getloc () const\fC [inline]\fP"

.PP
Locale access\&. 
.PP
\fBReturns\fP
.RS 4
A copy of the current locale\&.
.RE
.PP
If \fCimbue(loc)\fP has previously been called, then this function returns \fCloc\fP\&. Otherwise, it returns a copy of \fCstd::locale()\fP, the global C++ locale\&. 
.PP
Definition at line 775 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), std::money_put< _CharT, _OutIter >::do_put(), and std::ws()\&.
.SS "\fBlocale\fP std::ios_base::imbue (const \fBlocale\fP & __loc)"

.PP
Setting a new locale\&. 
.PP
\fBParameters\fP
.RS 4
\fI__loc\fP The new locale\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous locale\&.
.RE
.PP
Sets the new locale for this stream, and then invokes each callback with imbue_event\&. 
.PP
Referenced by std::basic_ios< _CharT, _Traits >::imbue()\&.
.SS "long& std::ios_base::iword (int __ix)\fC [inline]\fP"

.PP
Access to integer array\&. 
.PP
\fBParameters\fP
.RS 4
\fI__ix\fP Index into the array\&. 
.RE
.PP
\fBReturns\fP
.RS 4
A reference to an integer associated with the index\&.
.RE
.PP
The iword function provides access to an array of integers that can be used for any purpose\&. The array grows as required to hold the supplied index\&. All integers in the array are initialized to 0\&.
.PP
The implementation reserves several indices\&. You should use xalloc to obtain an index that is safe to use\&. Also note that since the array can grow dynamically, it is not safe to hold onto the reference\&. 
.PP
Definition at line 821 of file ios_base\&.h\&.
.SS "\fBstreamsize\fP std::ios_base::precision () const\fC [inline]\fP"

.PP
Flags access\&. 
.PP
\fBReturns\fP
.RS 4
The precision to generate on certain output operations\&.
.RE
.PP
Be careful if you try to give a definition of \fIprecision\fP here; see DR 189\&. 
.PP
Definition at line 701 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), and std::gamma_distribution< double >::operator()()\&.
.SS "\fBstreamsize\fP std::ios_base::precision (\fBstreamsize\fP __prec)\fC [inline]\fP"

.PP
Changing flags\&. 
.PP
\fBParameters\fP
.RS 4
\fI__prec\fP The new precision value\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous value of precision()\&. 
.RE
.PP

.PP
Definition at line 710 of file ios_base\&.h\&.
.SS "void*& std::ios_base::pword (int __ix)\fC [inline]\fP"

.PP
Access to void pointer array\&. 
.PP
\fBParameters\fP
.RS 4
\fI__ix\fP Index into the array\&. 
.RE
.PP
\fBReturns\fP
.RS 4
A reference to a void* associated with the index\&.
.RE
.PP
The pword function provides access to an array of pointers that can be used for any purpose\&. The array grows as required to hold the supplied index\&. All pointers in the array are initialized to 0\&.
.PP
The implementation reserves several indices\&. You should use xalloc to obtain an index that is safe to use\&. Also note that since the array can grow dynamically, it is not safe to hold onto the reference\&. 
.PP
Definition at line 842 of file ios_base\&.h\&.
.SS "void std::ios_base::register_callback (\fBevent_callback\fP __fn, int __index)"

.PP
Add the callback __fn with parameter __index\&. 
.PP
\fBParameters\fP
.RS 4
\fI__fn\fP The function to add\&. 
.br
\fI__index\fP The integer to pass to the function when invoked\&.
.RE
.PP
Registers a function as an event callback with an integer parameter to be passed to the function when invoked\&. Multiple copies of the function are allowed\&. If there are multiple callbacks, they are invoked in the order they were registered\&. 
.SS "\fBfmtflags\fP std::ios_base::setf (\fBfmtflags\fP __fmtfl)\fC [inline]\fP"

.PP
Setting new format flags\&. 
.PP
\fBParameters\fP
.RS 4
\fI__fmtfl\fP Additional flags to set\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous format control flags\&.
.RE
.PP
This function sets additional flags in format control\&. Flags that were previously set remain set\&. 
.PP
Definition at line 658 of file ios_base\&.h\&.
.PP
Referenced by std::__detail::operator>>()\&.
.SS "\fBfmtflags\fP std::ios_base::setf (\fBfmtflags\fP __fmtfl, \fBfmtflags\fP __mask)\fC [inline]\fP"

.PP
Setting new format flags\&. 
.PP
\fBParameters\fP
.RS 4
\fI__fmtfl\fP Additional flags to set\&. 
.br
\fI__mask\fP The flags mask for \fIfmtfl\fP\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous format control flags\&.
.RE
.PP
This function clears \fImask\fP in the format flags, then sets \fIfmtfl\fP \fC&\fP \fImask\fP\&. An example mask is \fCios_base::adjustfield\fP\&. 
.PP
Definition at line 675 of file ios_base\&.h\&.
.SS "static bool std::ios_base::sync_with_stdio (bool __sync = \fCtrue\fP)\fC [static]\fP"

.PP
Interaction with the standard C I/O objects\&. 
.PP
\fBParameters\fP
.RS 4
\fI__sync\fP Whether to synchronize or not\&. 
.RE
.PP
\fBReturns\fP
.RS 4
True if the standard streams were previously synchronized\&.
.RE
.PP
The synchronization referred to is \fIonly\fP that between the standard C facilities (e\&.g\&., stdout) and the standard C++ objects (e\&.g\&., cout)\&. User-declared streams are unaffected\&. See https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary 
.SS "void std::ios_base::unsetf (\fBfmtflags\fP __mask)\fC [inline]\fP"

.PP
Clearing format flags\&. 
.PP
\fBParameters\fP
.RS 4
\fI__mask\fP The flags to unset\&.
.RE
.PP
This function clears \fI__mask\fP in the format flags\&. 
.PP
Definition at line 690 of file ios_base\&.h\&.
.SS "\fBstreamsize\fP std::ios_base::width () const\fC [inline]\fP"

.PP
Flags access\&. 
.PP
\fBReturns\fP
.RS 4
The minimum field width to generate on output operations\&.
.RE
.PP
\fIMinimum field width\fP refers to the number of characters\&. 
.PP
Definition at line 724 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ios< _CharT, _Traits >::copyfmt(), and std::num_put< _CharT, _OutIter >::do_put()\&.
.SS "\fBstreamsize\fP std::ios_base::width (\fBstreamsize\fP __wide)\fC [inline]\fP"

.PP
Changing flags\&. 
.PP
\fBParameters\fP
.RS 4
\fI__wide\fP The new width value\&. 
.RE
.PP
\fBReturns\fP
.RS 4
The previous value of width()\&. 
.RE
.PP

.PP
Definition at line 733 of file ios_base\&.h\&.
.SS "static int std::ios_base::xalloc ()\fC [static]\fP"

.PP
Access to unique indices\&. 
.PP
\fBReturns\fP
.RS 4
An integer different from all previous calls\&.
.RE
.PP
This function returns a unique integer every time it is called\&. It can be used for any purpose, but is primarily intended to be a unique index for the iword and pword functions\&. The expectation is that an application calls xalloc in order to obtain an index in the iword and pword arrays that can be used without fear of conflict\&.
.PP
The implementation maintains a static variable that is incremented and returned on each invocation\&. xalloc is guaranteed to return an index that is safe to use in the iword and pword arrays\&. 
.SH "Member Data Documentation"
.PP 
.SS "const \fBfmtflags\fP std::ios_base::adjustfield\fC [static]\fP"

.PP
A mask of left|right|internal\&. Useful for the 2-arg form of \fCsetf\fP\&. 
.PP
Definition at line 378 of file ios_base\&.h\&.
.PP
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::internal(), std::left(), and std::right()\&.
.SS "const \fBopenmode\fP std::ios_base::app\fC [static]\fP"

.PP
Seek to end before each write\&. 
.PP
Definition at line 432 of file ios_base\&.h\&.
.PP
Referenced by std::basic_filebuf< _CharT, _Traits >::xsputn()\&.
.SS "const \fBopenmode\fP std::ios_base::ate\fC [static]\fP"

.PP
Open and seek to end immediately after opening\&. 
.PP
Definition at line 435 of file ios_base\&.h\&.
.PP
Referenced by std::basic_filebuf< _CharT, _Traits >::open()\&.
.SS "const \fBiostate\fP std::ios_base::badbit\fC [static]\fP"

.PP
Indicates a loss of integrity in an input or output sequence (such as an irrecoverable read error from a file)\&. 
.PP
Definition at line 402 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ios< _CharT, _Traits >::bad(), std::basic_ios< _CharT, _Traits >::fail(), std::basic_istream< char >::get(), and std::basic_istream< char >::read()\&.
.SS "const \fBfmtflags\fP std::ios_base::basefield\fC [static]\fP"

.PP
A mask of dec|oct|hex\&. Useful for the 2-arg form of \fCsetf\fP\&. 
.PP
Definition at line 381 of file ios_base\&.h\&.
.PP
Referenced by std::dec(), std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(), std::hex(), and std::oct()\&.
.SS "const \fBseekdir\fP std::ios_base::beg\fC [static]\fP"

.PP
Request a seek relative to the beginning of the stream\&. 
.PP
Definition at line 464 of file ios_base\&.h\&.
.PP
Referenced by std::basic_filebuf< _CharT, _Traits >::seekpos(), and __gnu_cxx::stdio_sync_filebuf< _CharT, _Traits >::seekpos()\&.
.SS "const \fBopenmode\fP std::ios_base::binary\fC [static]\fP"

.PP
Perform input and output in binary mode (as opposed to text mode)\&. This is probably not what you think it is; see https://gcc.gnu.org/onlinedocs/libstdc++/manual/fstreams.html#std.io.filestreams.binary\&. 
.PP
Definition at line 440 of file ios_base\&.h\&.
.SS "const \fBfmtflags\fP std::ios_base::boolalpha\fC [static]\fP"

.PP
Insert/extract \fCbool\fP in alphabetic rather than numeric format\&. 
.PP
Definition at line 326 of file ios_base\&.h\&.
.PP
Referenced by std::boolalpha(), std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(), and std::noboolalpha()\&.
.SS "const \fBseekdir\fP std::ios_base::cur\fC [static]\fP"

.PP
Request a seek relative to the current position within the sequence\&. 
.PP
Definition at line 467 of file ios_base\&.h\&.
.PP
Referenced by std::basic_filebuf< _CharT, _Traits >::seekoff(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff()\&.
.SS "const \fBfmtflags\fP std::ios_base::dec\fC [static]\fP"

.PP
Converts integer input or generates integer output in decimal base\&. 
.PP
Definition at line 329 of file ios_base\&.h\&.
.PP
Referenced by std::dec()\&.
.SS "const \fBseekdir\fP std::ios_base::end\fC [static]\fP"

.PP
Request a seek relative to the current end of the sequence\&. 
.PP
Definition at line 470 of file ios_base\&.h\&.
.PP
Referenced by std::basic_filebuf< _CharT, _Traits >::open(), and std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff()\&.
.SS "const \fBiostate\fP std::ios_base::eofbit\fC [static]\fP"

.PP
Indicates that an input operation reached the end of an input sequence\&. 
.PP
Definition at line 405 of file ios_base\&.h\&.
.PP
Referenced by std::time_get< _CharT, _InIter >::do_get(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_date(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_time(), std::time_get< _CharT, _InIter >::do_get_weekday(), std::time_get< _CharT, _InIter >::do_get_year(), std::basic_ios< _CharT, _Traits >::eof(), std::time_get< _CharT, _InIter >::get(), std::basic_istream< char >::getline(), std::basic_istream< _CharT, _Traits >::seekg(), std::basic_istream< _CharT, _Traits >::unget(), and std::ws()\&.
.SS "const \fBiostate\fP std::ios_base::failbit\fC [static]\fP"

.PP
Indicates that an input operation failed to read the expected characters, or that an output operation failed to generate the desired characters\&. 
.PP
Definition at line 410 of file ios_base\&.h\&.
.PP
Referenced by std::basic_ostream< _CharT, _Traits >::sentry::sentry(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_weekday(), std::time_get< _CharT, _InIter >::do_get_year(), std::basic_ios< _CharT, _Traits >::fail(), std::time_get< _CharT, _InIter >::get(), std::basic_istream< char >::getline(), and std::basic_istream< char >::operator>>()\&.
.SS "const \fBfmtflags\fP std::ios_base::fixed\fC [static]\fP"

.PP
Generate floating-point output in fixed-point notation\&. 
.PP
Definition at line 332 of file ios_base\&.h\&.
.PP
Referenced by std::fixed(), and std::hexfloat()\&.
.SS "const \fBfmtflags\fP std::ios_base::floatfield\fC [static]\fP"

.PP
A mask of scientific|fixed\&. Useful for the 2-arg form of \fCsetf\fP\&. 
.PP
Definition at line 384 of file ios_base\&.h\&.
.PP
Referenced by std::defaultfloat(), std::fixed(), std::hexfloat(), and std::scientific()\&.
.SS "const \fBiostate\fP std::ios_base::goodbit\fC [static]\fP"

.PP
Indicates all is well\&. 
.PP
Definition at line 413 of file ios_base\&.h\&.
.PP
Referenced by std::basic_istream< _CharT, _Traits >::sentry::sentry(), std::time_get< _CharT, _InIter >::do_get(), std::num_get< _CharT, _InIter >::do_get(), std::time_get< _CharT, _InIter >::do_get_monthname(), std::time_get< _CharT, _InIter >::do_get_weekday(), std::time_get< _CharT, _InIter >::do_get_year(), std::basic_ostream< _CharT, _Traits >::flush(), std::basic_istream< _CharT, _Traits >::get(), std::time_get< _CharT, _InIter >::get(), std::basic_istream< _CharT, _Traits >::getline(), std::basic_istream< _CharT, _Traits >::ignore(), std::basic_ostream< _CharT, _Traits >::operator<<(), std::operator>>(), std::basic_istream< _CharT, _Traits >::operator>>(), std::basic_istream< char >::operator>>(), std::basic_istream< _CharT, _Traits >::peek(), std::basic_istream< char >::peek(), std::basic_ostream< _CharT, _Traits >::put(), std::basic_istream< _CharT, _Traits >::read(), std::basic_istream< _CharT, _Traits >::readsome(), std::basic_istream< char >::readsome(), std::basic_istream< _CharT, _Traits >::seekg(), std::basic_ostream< _CharT, _Traits >::seekp(), std::basic_istream< _CharT, _Traits >::sync(), and std::basic_istream< _CharT, _Traits >::unget()\&.
.SS "const \fBfmtflags\fP std::ios_base::hex\fC [static]\fP"

.PP
Converts integer input or generates integer output in hexadecimal base\&. 
.PP
Definition at line 335 of file ios_base\&.h\&.
.PP
Referenced by std::num_get< _CharT, _InIter >::do_get(), std::num_put< _CharT, _OutIter >::do_put(), and std::hex()\&.
.SS "const \fBopenmode\fP std::ios_base::in\fC [static]\fP"

.PP
Open for input\&. Default for \fCifstream\fP and fstream\&. 
.PP
Definition at line 443 of file ios_base\&.h\&.
.PP
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(), std::basic_filebuf< _CharT, _Traits >::showmanyc(), std::basic_filebuf< _CharT, _Traits >::underflow(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::underflow(), and std::basic_filebuf< _CharT, _Traits >::xsgetn()\&.
.SS "const \fBfmtflags\fP std::ios_base::internal\fC [static]\fP"

.PP
Adds fill characters at a designated internal point in certain generated output, or identical to \fCright\fP if no such point is designated\&. 
.PP
Definition at line 340 of file ios_base\&.h\&.
.PP
Referenced by std::internal()\&.
.SS "const \fBfmtflags\fP std::ios_base::left\fC [static]\fP"

.PP
Adds fill characters on the right (final positions) of certain generated output\&. (I\&.e\&., the thing you print is flush left\&.) 
.PP
Definition at line 344 of file ios_base\&.h\&.
.PP
Referenced by std::num_put< _CharT, _OutIter >::do_put(), and std::left()\&.
.SS "const \fBfmtflags\fP std::ios_base::oct\fC [static]\fP"

.PP
Converts integer input or generates integer output in octal base\&. 
.PP
Definition at line 347 of file ios_base\&.h\&.
.PP
Referenced by std::oct()\&.
.SS "const \fBopenmode\fP std::ios_base::out\fC [static]\fP"

.PP
Open for output\&. Default for \fCofstream\fP and fstream\&. 
.PP
Definition at line 446 of file ios_base\&.h\&.
.PP
Referenced by std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekoff(), std::basic_stringbuf< _CharT, _Traits, _Alloc >::seekpos(), and std::basic_filebuf< _CharT, _Traits >::xsputn()\&.
.SS "const \fBfmtflags\fP std::ios_base::right\fC [static]\fP"

.PP
Adds fill characters on the left (initial positions) of certain generated output\&. (I\&.e\&., the thing you print is flush right\&.) 
.PP
Definition at line 351 of file ios_base\&.h\&.
.PP
Referenced by std::right()\&.
.SS "const \fBfmtflags\fP std::ios_base::scientific\fC [static]\fP"

.PP
Generates floating-point output in scientific notation\&. 
.PP
Definition at line 354 of file ios_base\&.h\&.
.PP
Referenced by std::hexfloat(), and std::scientific()\&.
.SS "const \fBfmtflags\fP std::ios_base::showbase\fC [static]\fP"

.PP
Generates a prefix indicating the numeric base of generated integer output\&. 
.PP
Definition at line 358 of file ios_base\&.h\&.
.PP
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::noshowbase(), and std::showbase()\&.
.SS "const \fBfmtflags\fP std::ios_base::showpoint\fC [static]\fP"

.PP
Generates a decimal-point character unconditionally in generated floating-point output\&. 
.PP
Definition at line 362 of file ios_base\&.h\&.
.PP
Referenced by std::noshowpoint(), and std::showpoint()\&.
.SS "const \fBfmtflags\fP std::ios_base::showpos\fC [static]\fP"

.PP
Generates a + sign in non-negative generated numeric output\&. 
.PP
Definition at line 365 of file ios_base\&.h\&.
.PP
Referenced by std::noshowpos(), and std::showpos()\&.
.SS "const \fBfmtflags\fP std::ios_base::skipws\fC [static]\fP"

.PP
Skips leading white space before certain input operations\&. 
.PP
Definition at line 368 of file ios_base\&.h\&.
.PP
Referenced by std::noskipws(), std::__detail::operator>>(), and std::skipws()\&.
.SS "const \fBopenmode\fP std::ios_base::trunc\fC [static]\fP"

.PP
Truncate an existing stream when opening\&. Default for \fCofstream\fP\&. 
.PP
Definition at line 449 of file ios_base\&.h\&.
.SS "const \fBfmtflags\fP std::ios_base::unitbuf\fC [static]\fP"

.PP
Flushes output after each output operation\&. 
.PP
Definition at line 371 of file ios_base\&.h\&.
.PP
Referenced by std::nounitbuf(), and std::unitbuf()\&.
.SS "const \fBfmtflags\fP std::ios_base::uppercase\fC [static]\fP"

.PP
Replaces certain lowercase letters with their uppercase equivalents in generated output\&. 
.PP
Definition at line 375 of file ios_base\&.h\&.
.PP
Referenced by std::num_put< _CharT, _OutIter >::do_put(), std::nouppercase(), and std::uppercase()\&.

.SH "Author"
.PP 
Generated automatically by Doxygen for libstdc++ from the source code\&.