---
name: "Pipe"
section: "3cc"
platform: "linux"
package: "libcommoncpp2-dev"
version: "1.0.13-5"
release: "Debian 3.1 (Sarge)"
platforms: ["linux"]
url: "https://new.carta.tech/Pipe"
---

# Pipe(3cc)

The Pipe uses system kernel buffering to hold data being passed either between two execution contexts within the same process, or between different processes. kernel buffering between processes and/or threads.

## NAME

Pipe - The Pipe uses system kernel buffering to hold data being passed either between two execution contexts within the same process, or between different processes. kernel buffering between processes and/or threads.

## SYNOPSIS

`#include <file.h>`

### Public Methods

bool **operator!** ()\
 *Used to see if the pipe has any open entities.* int **receive** (void \*addr)\
 *Perform an object atomic transfer of data from a pipe.* int **send** (void \*addr)\
 *Perform an object atomic transfer of data to a pipe.* bool **isValid** (void)\
 *Verify this object is 'valid'.*

### Protected Methods

int **getSize** (void)\
 *Get the object size for atomic operations.* void **endSender** (void)\
 *Sender is often used for implementing a fork()'d message port between processes.* void **endReceiver** (void)\
 *Receiver is often used for implementing a fork()'d message port between processes.* **Pipe** (int **size**=512, int count=1)\
 *Create a kernel pipe descriptor set using pipe().* virtual **~Pipe** ()\
 *Destroy the pipe and kernel descriptor resources.* **Pipe** (const Pipe &orig)\
 *Create a pipe as a duplicate of an existing pipe.* Pipe & **operator=** (const Pipe &orig)\
 void **sender** (void)\
 void **receiver** (void)\
 int **read** (void \*buf, int len)\
 int **write** (void \*buf, int len)\

### Protected Attributes

int **fd** \[2\]\
 int **objcount**\
 int **objsize**\

## DETAILED DESCRIPTION

The Pipe uses system kernel buffering to hold data being passed either between two execution contexts within the same process, or between different processes. kernel buffering between processes and/or threads.

Unlike thread's '**Buffer**', Pipe uses system descriptors and kernel memory. Under Posix, the size of the pipe and associated kernel memory is always a fixed constant as defined by \_PC\_PIPE\_BUF. The Common C++ 'pipe' class primarily deals with 'atomic' transfers of fixed sized objects through pipes. Pipes may pass data arbitrarily and can also be used through the 'pipestream' class.

The 'Pipe' class is not meant to be a true 'public' class, but as a builder class for deriving other classes.

**Author:**  David Sugar \<dyfet@ostel.com\>

## CONSTRUCTOR & DESTRUCTOR DOCUMENTATION

### Pipe::Pipe (int size = 512, int count = 1)` [protected]`

Create a kernel pipe descriptor set using pipe().

On systems which allow the pipe kernel buffer to be defined, a size for aligned atomic transfers can be set, as well as the number of atomic objects the kernel will buffer. On Posix systems, these options are ignored.

**Parameters:**

- *size*

  *objsize of atomic objects to send.*

- *count*

  *count of atomic objects to kernel buffer.*

### virtual Pipe::~Pipe ()` [protected, virtual]`

*Destroy the pipe and kernel descriptor resources.*

### Pipe::Pipe (const Pipe & orig)` [protected]`

*Create a pipe as a duplicate of an existing pipe.*

**Parameters:**

- *orig*

  *pipe to duplicate.*

## MEMBER FUNCTION DOCUMENTATION

### void Pipe::endReceiver (void)` [inline, protected]`

*Receiver is often used for implementing a fork()'d message port between processes.*

*By stopping the receiver, the current pipe can then only be used for sending, and the receiver is presumed to be in the other half of a fork()'d process.*

**See also:**  **endSender**

### void Pipe::endSender (void)` [inline, protected]`

*Sender is often used for implementing a fork()'d message port between processes.*

*By stopping the sender, the current pipe can then only be used for receiving, and the sender is presumed to be in the other half of a fork()'d process.*

**See also:**  **endReceiver**

### int Pipe::getSize (void)` [inline, protected]`

*Get the object size for atomic operations.*

**Returns:**  *size of atomic operations.*

### bool Pipe::isValid (void)

*Verify this object is 'valid'.*

**Returns:**  *true if valid.*

### bool Pipe::operator! ()

*Used to see if the pipe has any open entities.*

### Pipe& Pipe::operator= (const Pipe & orig)` [protected]`

### int Pipe::read (void \* buf, int len)` [inline, protected]`

### int Pipe::receive (void \* addr)` [inline]`

*Perform an object atomic transfer of data from a pipe.*

**Returns:**  *number of bytes actually read if successful.*

**Parameters:**

- *addr*

  *pointer to store read data.*

### void Pipe::receiver (void)` [inline, protected]`

### int Pipe::send (void \* addr)` [inline]`

*Perform an object atomic transfer of data to a pipe.*

**Returns:**  *number of bytes written if successful.*

**Parameters:**

- *addr*

  *pointer to write data from.*

### void Pipe::sender (void)` [inline, protected]`

### int Pipe::write (void \* buf, int len)` [inline, protected]`

## MEMBER DATA DOCUMENTATION

### int Pipe::fd\[2\]` [protected]`

### int Pipe::objcount` [protected]`

### int Pipe::objsize` [protected]`

## AUTHOR

*Generated automatically by Doxygen for CommonC++ from the source code.*