Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Boost
C++ Libraries
...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Attempt to read a certain amount of data at the specified offset before returning.
template< typename SyncRandomAccessReadDevice, typename Allocator, typename CompletionCondition> std::size_t read_at( SyncRandomAccessReadDevice & d, boost::uint64_t offset, basic_streambuf< Allocator > & b, CompletionCondition completion_condition, boost::system::error_code & ec);
This function is used to read a certain number of bytes of data from a random access device at the specified offset. The call will block until one of the following conditions is true:
This operation is implemented in terms of one or more calls to the device's read_some_at function.
The device from which the data is to be read. The type must support the SyncRandomAccessReadDevice concept.
The offset at which the data will be read.
The basic_streambuf object into which the data will be read.
The function object to be called to determine whether the read operation is complete. The signature of the function object must be:
bool completion_condition( // Result of latest read_some_at operation. const boost::system::error_code& error, // Number of bytes transferred so far. std::size_t bytes_transferred );
A return value of true indicates that the read operation is complete. False indicates that further calls to the device's read_some_at function are required.
Set to indicate what error occurred, if any.
The number of bytes read. If an error occurs, returns the total number of bytes successfully transferred prior to the error.