OutPipe is a class for writing output to an arbitrary destination such as a file, network socket, or encryption/compression codec. It's often used as the underlying output destination of an OutStream.

OutPipe is a lower-level class than OutStream and is more akin to a Unix file descriptor. When the OutPipe writes to a file or network socket, each call to write() invokes a system call to the OS kernel. Therefore, when writing directly to an OutPipe, it's best to write medium-to-large quantities of data (say, several KB) at a time in order to minimize system call overhead.

If writing small amounts of data (say, a few bytes) at a time -- for example, to parse text or binary formats -- it's better to work with OutStream or StringWriter instead.

Header File

#include <ply-runtime/io/Pipe.h>

Also included from <ply-runtime/Base.h>.

Member Functions

template <typename T>
T* cast() [code]

Cast this OutPipe to a derived type such as OutPipe_Win32, OutPipe_FD or OutPipe_Winsock in order to access additional functions or data members. A runtime check is performed to ensure the cast is valid.

bool write(ConstBufferView buf) [code]

Attempts to write the entire contents of buf to the output destination. This call may block depending on the state of the OutPipe. For example, if the OutPipe is a network socket or a pipe, and the process on the other end is not reading quickly enough, write() may block. Returns true if successful. Return false if the write fails such as when attempting to a network socket that was closed prematurely.

bool flush(bool toDevice = true) [code]

Flushes any application-level memory buffers in the same manner as flushMem(), then performs an implementation-specific device flush if toDevice is true. For example, if toDevice is true, this will call fsync() on when writing to a POSIX file descriptor or FlushFileBuffers() when writing to a Windows file handle. Returns true unless there's an error in the implementation-specific device flush.

void flushMem() [code]

Flushes any application-level memory buffers maintained by the OutPipe will be flushed to their destination. Appropriate to use when the OutPipe is a line feed filter or any kind of application-level conversion, compression or encryption filter.

u64 seek(s64 pos, SeekDir seekDir) [code]

If the output destination is seekable, seeks to the specified file offset and returns the current file offset. To get the current file offset without changing it, call seek(0, SeekDir::Cur).