Copies bytes from a source buffer to a target buffer.
std::size_t buffer_copy( const mutable_buffer & target, const const_buffer & source);
A modifiable buffer representing the memory region to which the bytes will be copied.
A non-modifiable buffer representing the memory region from which the bytes will be copied.
The number of bytes copied.
The number of bytes copied is the lesser of:
This function is implemented in terms of
and consequently it cannot be used to copy between overlapping memory regions.