Boost C++ Libraries of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Click here to view the latest version of this page.

write (5 of 6 overloads)

Write a certain amount of data to a stream before returning.

    typename SyncWriteStream,
    typename Allocator,
    typename CompletionCondition>
std::size_t write(
    SyncWriteStream & s,
    basic_streambuf< Allocator > & b,
    CompletionCondition completion_condition);

This function is used to write a certain number of bytes of data to a stream. The call will block until one of the following conditions is true:

This operation is implemented in terms of zero or more calls to the stream's write_some function.



The stream to which the data is to be written. The type must support the SyncWriteStream concept.


The basic_streambuf object from which data will be written.


The function object to be called to determine whether the write operation is complete. The signature of the function object must be:

std::size_t completion_condition(
  // Result of latest write_some operation.
  const boost::system::error_code& error,

  // Number of bytes transferred so far.
  std::size_t bytes_transferred

A return value of 0 indicates that the write operation is complete. A non-zero return value indicates the maximum number of bytes to be written on the next call to the stream's write_some function.

Return Value

The number of bytes transferred.



Thrown on failure.