Memory channels

Memory channels allow a region of memory to be accessed as a channel.

There are three memory channel types, all of which support both sequential and direct access (see Channel concepts):

• sk::cio::imemchannel - read-only access to a memory region.

• sk::cio::omemchannel - write-only access to a memory region.

• sk::cio::memchannel - bidirectional access to a memory region.

The value_type of a memory channel is std::byte.

Include files

• For imemchannel, include <sk/cio/memchannel/imemchannel.hxx>

• For omemchannel, include <sk/cio/memchannel/omemchannel.hxx>

• For memchannel, include <sk/cio/memchannel/memchannel.hxx>

• For all three types, include <sk/cio/memchannel.hxx> or <sk/cio.hxx>.

Opening a memory channel

Before a memory channel can be used, it must be opened by providing the address and size of the memory region. For convenience, overloads are provided for open() to allow opening with std::byte, char, signed char and unsigned char.

imemchannel can be opened with a const memory region, while omemchannel and memchannel require a mutable region.

Opening imemchannel

auto open(T const *begin, T const *end)
    -> expected<void, std::error_code>;

auto open(T const *begin, std::size_t size)
    -> expected<void, std::error_code>;

T can be std::byte, char, signed char or unsigned char.

Opening omemchannel and memchannel

auto open(T *begin, T *end)
    -> expected<void, std::error_code>;

auto open(T *begin, std::size_t size)
    -> expected<void, std::error_code>;

T can be std::byte, char, signed char or unsigned char.

Reading and writes memory channels

Memory channels have similar semantics to files. The memory channel can be read or written sequentially until reaching the end of the memory region, at which point sk::cio::error::end_of_file will be returned. Attemping to write data which would be partially past the end of the region will return a short read or write.

memchannel uses separate pointers for the sequential read and write position. This means you can write data to the channel and then later read back the same data without adjusting the seek position.