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std::basic_ostream::write

From cppreference.com
< cpp‎ | io‎ | basic ostream
basic_ostream& write( const char_type* s, std::streamsize count );

Behaves as an UnformattedOutputFunction. After constructing and checking the sentry object, outputs the characters from successive locations in the character array whose first element is pointed to by s. Characters are inserted into the output sequence until one of the following occurs:

  • exactly count characters are inserted
  • inserting into the output sequence fails (in which case setstate(badbit) is called)

Contents

[edit] Parameters

s - pointer to the character string to write
count - number of characters to write

[edit] Return value

*this

[edit] 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.

[edit] Notes

This function is not overloaded for the types signed char or unsigned char, unlike the formatted operator<<

Also, unlike the formatted output functions, this function does not set the failbit on failure.

When using a non-converting locale (the default locale is non-converting), the overrider of this function in std::basic_ofstream may be optimized for zero-copy bulk I/O (by means of overriding std::streambuf::xsputn)

[edit] Example

This function may be used to output object representations, i.e. binary output

#include <iostream>
 
int main()
{
    int n = 0x41424344;
    std::cout.write(reinterpret_cast<char*>(&n), sizeof n) << '\n';
 
    char c[]="This is sample text.";
    std::cout.write(c,4)<<'\n';
}

Possible output:

DCBA
This

[edit] See also

inserts character data
(function template) [edit]
inserts a character
(public member function) [edit]