NAME¶

std::basic_istream::get - std::basic_istream::get

Synopsis¶

int_type get(); (1)
basic_istream& get( char_type& ch ); (2)
basic_istream& get( char_type* s, std::streamsize count ); (3)
basic_istream& get( char_type* s, std::streamsize count, char_type delim ); (4)
basic_istream& get( basic_streambuf& strbuf ); (5)
basic_istream& get( basic_streambuf& strbuf, char_type delim ); (6)

Extracts character or characters from stream.

All versions behave as UnformattedInputFunctions. After constructing and checking
the sentry object, these functions perform the following:

1) Reads one character and returns it if available. Otherwise, returns Traits::eof()
and sets failbit and eofbit.
2) Reads one character and stores it to ch if available. Otherwise, leaves ch
unmodified and sets failbit and eofbit. Note that this function is not overloaded on
the types signed char and unsigned char, unlike the formatted character input
operator>>.
3) Same as get(s, count, widen('\n')), that is, reads at most std::max(0, count - 1)
characters and stores them into character string pointed to by s until '\n' is
found.
4) Reads characters and stores them into the successive locations of the character
array whose first element is pointed to by s. Characters are extracted and stored
until any of the following occurs:
* count is less than 1 or count - 1 characters have been stored.
* end of file condition occurs in the input sequence (setstate(eofbit) is called).
* the next available input character c equals delim, as determined by
Traits::eq(c, delim). This character is not extracted (unlike getline()).
In any case, if count > 0, a null character (CharT() is stored in the next
successive location of the array.
5) Same as get(strbuf, widen('\n')), that is, reads available characters and inserts
them to the given basic_streambuf object until '\n' is found.
6) Reads characters and inserts them to the output sequence controlled by the given
basic_streambuf object. Characters are extracted and inserted into strbuf until any
of the following occurs:
* end of file condition occurs in the input sequence.
* inserting into the output sequence fails (in which case the character that could
not be inserted, is not extracted).
* the next available input character c equals delim, as determined by
Traits::eq(c, delim). This character is not extracted.
* an exception occurs (in which case the exception is caught and not rethrown).

If no characters were extracted, calls setstate(failbit).

All versions set the value of gcount() to the number of characters extracted.

Parameters¶

ch - reference to the character to write the result to
s - pointer to the character string to store the characters to
count - size of character string pointed to by s
delim - delimiting character to stop the extraction at. It is not extracted and not
stored
strbuf - stream buffer to read the content to

Return value¶

1) The extracted character or Traits::eof().
2-6) *this

Exceptions¶

failure if an error occurred (the error state flag is not goodbit) and exceptions()
is set to throw for that state.

If an internal operation throws an exception, it is caught and badbit is set. If
exceptions() is set for badbit, the exception is rethrown.

Example¶

// Run this code

#include <iostream>
#include <sstream>

int main()
{
std::istringstream s1("Hello, world.");
char c1 = s1.get(); // reads 'H'
std::cout << "after reading " << c1 << ", gcount() == " << s1.gcount() << '\n';

char c2;
s1.get(c2); // reads 'e'
char str[5];
s1.get(str, 5); // reads "llo,"
std::cout << "after reading " << str << ", gcount() == " << s1.gcount() << '\n';

std::cout << c1 << c2 << str;
s1.get(*std::cout.rdbuf()); // reads the rest, not including '\n'
std::cout << "\nAfter the last get(), gcount() == " << s1.gcount() << '\n';
}

Output:¶

after reading H, gcount() == 1
after reading llo,, gcount() == 4
Hello, world.
After the last get(), gcount() == 7

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
the effect of overload (5) was get(s, corrected to
LWG 370 C++98 count, widen('\n')), get(strbuf, widen('\n'))
which is the effect of overload (3)
LWG 531 C++98 overloads (3,4) could not handle the no character is
case where count is non-positive extracted in this case

See also¶

read extracts blocks of characters
(public member function)
operator>> extracts formatted data
(public member function)
operator>>(std::basic_istream) extracts characters and character arrays
(function template)