Write all of the supplied data at the specified offset before returning.
template< typename SyncRandomAccessWriteDevice, typename Allocator> std::size_t write_at( SyncRandomAccessWriteDevice & d, uint64_t offset, basic_streambuf< Allocator > & b);
This function is used to write a certain number of bytes of data to a random access device at a specified offset. The call will block until one of the following conditions is true:
basic_streambufhas been written.
This operation is implemented in terms of zero or more calls to the device's write_some_at function.
The device to which the data is to be written. The type must support the SyncRandomAccessWriteDevice concept.
The offset at which the data will be written.
basic_streambuf object from
which data will be written.
The number of bytes transferred.
Thrown on failure.
This overload is equivalent to calling:
boost::asio::write_at( d, 42, b, boost::asio::transfer_all());