This is simpler than using
getistream() or
getostream() and constructing
a std::istreambuf_iterator or a
std::ostreambuf_iterator:
#include <x/fditer.H> x::fdbase filedesc=x::fd::base::open("file", O_RDONLY); std::string str; std::copy(x::fdinputiter(filedesc, 1024), x::fdinputiter(), std::back_insert_iterator<std::string>(str));
x::fdinputiter
constructs an input iterator that reads from the underlying file
descriptor transport. The second optional parameter is the size of
the internal buffer, which defaults to the
x::fd::buffer_size
property.
The default constructor instantiates an ending iterator value.
x::fdbase filedesc=x::fd::base::create("file", 0777); std::string str; x::fd::outputiter iter(filedesc, 1024); iter=std::copy(str.begin(), str.end(), iter); // ... iter.flush();
x::fdoutputiter
constructs an output iterator that writes to the underlying file
descriptor transport, also using an internal buffer.
It's destructor does not flush unwritten buffer contents,
flush() must be explicitly invoked to do that.
An input and an output iterator can be constructed concurrently, however they are completely independent from each other, and use their own separate buffers. Reading from the input iterator does not flush the output iterator, and writing to the output iterator does not clear the input buffer.
The iterators can be constructed from any subclass of the
file descriptor transport superclass,
and not just x::fd. This includes
x::gnutls::session.
The iterators also hold their own reference to the file descriptor
transport object they're iterating over.
Using
std::istreambuf_iterator or
std::ostreambuf_iterator requires that the
underlying stream objects remain in scope.
x::fdinputiter and
x::fdoutputiter, in addition to being
references to reference-counted objects themselves, hold their own
reference on the underlying reference-counted file descriptor transport
superclass.
The iterators throw an exception if the underlying file
descriptor transport's pubwrite()
returns 0, indicating an error writing to the file descriptor.
An exception also gets thrown when
pubread() returns 0
with errno set, indicating an error reading the
underlying file descriptor.
pubread() returning 0
with errno cleared indicates an ordinary and of
file, and the input iterator gets set to the ending sequence
value.