30 Input/output library [input.output]

Effects: Constructs an object of class basic_­ostream, initializing the base class subobject with basic_­ios<charT, traits>​::​init(sb) ([basic.ios.cons]).

Postconditions: rdbuf() == sb.

Effects: Move constructs from the rvalue rhs. This is accomplished by default constructing the base class and calling basic_­ios<charT, traits>​::​move(rhs) to initialize the base class.

Effects: Destroys an object of class basic_­ostream.

Remarks: Does not perform any operations on rdbuf().

Effects: As if by swap(rhs).

Returns: *this.

Effects: Calls basic_­ios<charT, traits>​::​swap(rhs).

If os.good() is nonzero, prepares for formatted or unformatted output. If os.tie() is not a null pointer, calls os.tie()->flush().318

If, after any preparation is completed, os.good() is true, ok_­ == true otherwise, ok_­ == false. During preparation, the constructor may call setstate(failbit) (which may throw ios_­base​::​​failure ([iostate.flags]))319

If (os.flags() & ios_­base​::​unitbuf) && !uncaught_­exceptions() && os.good() is true, calls os.rdbuf()->pubsync(). If that function returns -1, sets badbit in os.rdstate() without propagating an exception.

Effects: Returns ok_­.

Returns: If fail() != false, returns pos_­type(-1) to indicate failure. Otherwise, returns rdbuf()->​pubseekoff(​0, cur, out).

Effects: If fail() != true, executes rdbuf()->pubseekpos(pos, ios_­base​::​out). In case of failure, the function calls setstate(failbit) (which may throw ios_­base​::​failure).

Returns: *this.

Effects: If fail() != true, executes rdbuf()->pubseekoff(off, dir, ios_­base​::​out). In case of failure, the function calls setstate(failbit) (which may throw ios_­base​::​failure).

Returns: *this.

Effects: The classes num_­get<> and num_­put<> handle locale-dependent numeric formatting and parsing. These inserter functions use the imbued locale value to perform numeric formatting. When val is of type bool, long, unsigned long, long long, unsigned long long, double, long double, or const void*, the formatting conversion occurs as if it performed the following code fragment:

bool failed = use_facet<
  num_put<charT, ostreambuf_iterator<charT, traits>>
    >(getloc()).put(*this, *this, fill(), val).failed();

When val is of type short the formatting conversion occurs as if it performed the following code fragment:

ios_base::fmtflags baseflags = ios_base::flags() & ios_base::basefield;
bool failed = use_facet<
  num_put<charT, ostreambuf_iterator<charT, traits>>
    >(getloc()).put(*this, *this, fill(),
    baseflags == ios_base::oct || baseflags == ios_base::hex
      ? static_cast<long>(static_cast<unsigned short>(val))
      : static_cast<long>(val)).failed();

When val is of type int the formatting conversion occurs as if it performed the following code fragment:

ios_base::fmtflags baseflags = ios_base::flags() & ios_base::basefield;
bool failed = use_facet<
  num_put<charT, ostreambuf_iterator<charT, traits>>
    >(getloc()).put(*this, *this, fill(),
    baseflags == ios_base::oct || baseflags == ios_base::hex
      ? static_cast<long>(static_cast<unsigned int>(val))
      : static_cast<long>(val)).failed();

When val is of type unsigned short or unsigned int the formatting conversion occurs as if it performed the following code fragment:

bool failed = use_facet<
  num_put<charT, ostreambuf_iterator<charT, traits>>
    >(getloc()).put(*this, *this, fill(),
      static_cast<unsigned long>(val)).failed();

When val is of type float the formatting conversion occurs as if it performed the following code fragment:

bool failed = use_facet<
  num_put<charT, ostreambuf_iterator<charT, traits>>
    >(getloc()).put(*this, *this, fill(),
      static_cast<double>(val)).failed();

The first argument provides an object of the ostreambuf_­iterator<> class which is an iterator for class basic_­ostream<>. It bypasses ostreams and uses streambufs directly. Class locale relies on these types as its interface to iostreams, since for flexibility it has been abstracted away from direct dependence on ostream. The second parameter is a reference to the base class subobject of type ios_­base. It provides formatting specifications such as field width, and a locale from which to obtain other facets. If failed is true then does setstate(badbit), which may throw an exception, and returns.

Returns: *this.

Effects: None. Does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: pf(*this).321

Effects: Calls pf(*this). This inserter does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: *this.322

Effects: Calls pf(*this). This inserter does not behave as a formatted output function (as described in [ostream.formatted.reqmts]).

Returns: *this.

Effects: Behaves as an unformatted output function. After the sentry object is constructed, if sb is null calls setstate(badbit) (which may throw ios_­base​::​failure).

Gets characters from sb and inserts them in *this. Characters are read from sb and inserted until any of the following occurs:

• (8.1)

  end-of-file occurs on the input sequence;

• (8.2)

  inserting in the output sequence fails (in which case the character to be inserted is not extracted);

• (8.3)

  an exception occurs while getting a character from sb.

If the function inserts no characters, it calls setstate(failbit) (which may throw ios_­base​::​​failure ([iostate.flags])). If an exception was thrown while extracting a character, the function sets failbit in error state, and if failbit is on in exceptions() the caught exception is rethrown.

Returns: *this.

Effects: Equivalent to:

return *this << s;

where s is an implementation-defined NTCTS.

Effects: Behaves as a formatted output function of out. Constructs a character sequence seq. If c has type char and the character type of the stream is not char, then seq consists of out.widen(c); otherwise seq consists of c. Determines padding for seq as described in [ostream.formatted.reqmts]. Inserts seq into out. Calls os.width(0).

Returns: out.

Requires: s shall not be a null pointer.

Effects: Behaves like a formatted inserter (as described in [ostream.formatted.reqmts]) of out. Creates a character sequence seq of n characters starting at s, each widened using out.widen() ([basic.ios.members]), where n is the number that would be computed as if by:

• (4.1)

  traits​::​length(s) for the overload where the first argument is of type basic_­ostream<charT, traits>& and the second is of type const charT*, and also for the overload where the first argument is of type basic_­ostream<char, traits>& and the second is of type const char*,

• (4.2)

  char_­traits<char>​::​length(s) for the overload where the first argument is of type basic_­ostream<charT, traits>& and the second is of type const char*,

• (4.3)

  traits​::​length(reinterpret_­cast<const char*>(s)) for the other two overloads.

Determines padding for seq as described in [ostream.formatted.reqmts]. Inserts seq into out. Calls width(0).

Returns: out.