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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
OS Components & Operations
Persistent Publish/Subscribe Developer's Guide
PPS API reference
This chapter describes the publicly visible PPS API functions and data types.
pps_decoder_pop()
Ascend to the parent of the current node

QNX Momentics IDE User's Guide
This User's Guide describes version 7.1 of the Integrated Development Environment (IDE) that's part of the QNX Momentics tool suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
- Quickstart Guide
- OS Components & Operations
  - Adaptive Partitioning User's Guide
  - Boot Optimization Guide
    The Boot Optimization Guide describes techniques you can use to reduce the time from your board's initial power on until you have a fully functional QNX system running on the board.
  - Building Embedded Systems
    The Building Embedded Systems guide is intended for developers who are developing or building BSPs for QNX Neutrino RTOS embedded systems.
  - Core Networking Stack User's Guide
    This guide introduces you to the QNX Neutrino Core Networking stack and its manager, io-pkt.
  - Customizing a BSP
    While QNX provides Board Support Packages (BSPs) for many common platforms and their individual variants, in some cases, you need a BSP for a board that QNX does not provide. If this is the case, you can modify a QNX BSP or develop your own.
  - Device Publishers Developer's Guide
  - High Availability Framework Developer's Guide
  - High-Performance Networking Stack (io-sock) User's Guide
    This guide contains instructions for implementing and using the QNX Neutrino High-Performance Networking Stack and its manager, io-sock.
  - Instant Device Activation
  - Migrating to QNX SDP 7.1
  - PCI Server User's Guide
  - Persistent Publish/Subscribe Developer's Guide
    - QNX Neutrino PPS Service
      The QNX Neutrino Persistent Publish/Subscribe (PPS) service is a small, extensible publish and subscribe service that offers persistence across reboots. It's designed to provide a simple and easy-to-use solution for both publish/subscribe and persistence in embedded systems, answering a need for building loosely connected systems using asynchronous publications and notifications.
    - Objects and Their Attributes
      The QNX Neutrino PPS service is a system with objects whose properties a publisher can modify.
    - Persistence
    - Publishing
    - Subscribing
      PPS clients can subscribe to multiple objects, and PPS objects can have multiple subscribers. When a publisher changes an object, all clients subscribed to that object are informed of the change.
    - Options and Qualifiers
    - Server Objects
    - PPS Encoding and Decoding API
      The PPS encoding and decoding API makes it easy to encode and decode complex data structures such as arrays and objects in PPS attributes and to ensure attributes are properly typed.
    - PPS API reference
      This chapter describes the publicly visible PPS API functions and data types.
      - pps_attrib_flags_t
        The states for PPS objects and attributes
      - pps_attrib_t
        pps_attrib_t
      - pps_decoder_cleanup()
        Clean up a pps_decoder_t structure
      - pps_decoder_dump_tree()
        Write a decoded PPS data structure in human-readable format to a file
      - pps_decoder_error_t
        pps_decoder_error_t
      - pps_decoder_flags()
        Return the flags associated with the current or named attribute
      - pps_decoder_get_bool()
        Extract a Boolean value from the current or named node
      - pps_decoder_get_double()
        Extract a double value from the current or named node
      - pps_decoder_get_int()
        Extract an integer value from the current or named node
      - pps_decoder_get_int64()
        Extract a 64-bit integer value from the current or named node
      - pps_decoder_get_state()
        Return the current state of the decoder
      - pps_decoder_get_string()
        Extract a string value from a node
      - pps_decoder_goto_index()
        Advance to the indicated element or property of an array or object
      - pps_decoder_initialize()
        Initialize the decoder structure
      - pps_decoder_is_integer()
        Test whether a node is an integer
      - pps_decoder_length()
        Return the number of elements or properties in the current object or array
      - pps_decoder_name()
        Return the name of the current node
      - pps_decoder_next()
        Advance to the next node
      - pps_decoder_parse_json_str()
        Parse a string of JSON-formatted data
      - pps_decoder_parse_pps_str()
        Parse a string of PPS-formatted data
      - pps_decoder_pop()
        Ascend to the parent of the current node
      - pps_decoder_push()
        Descend into a lower-level node
      - pps_decoder_push_array()
        Descend into a lower-level array
      - pps_decoder_push_object()
        Descend into a lower-level object
      - pps_decoder_reset()
        Reset the pps_decoder_t structure
      - pps_decoder_set_position()
        Position the decoder at the specified node
      - pps_decoder_set_state()
        Set the state of the decoder
      - pps_decoder_state_t
        pps_decoder_state_t
      - pps_decoder_status()
        Return the current error status of the decoder
      - pps_decoder_t
        pps_decoder_t
      - pps_decoder_type()
        Return the data type of the current or named node
      - pps_encoder_add_bool()
        Add a Boolean to the current object or array
      - pps_encoder_add_double()
        Add a double to the current object or array
      - pps_encoder_add_from_decoder()
        Add part or all of the contents of a decoder to an encoder
      - pps_encoder_add_int()
        Add an integer to the current object or array
      - pps_encoder_add_int64()
        Add a 64-bit integer to the current object or array
      - pps_encoder_add_json()
        Add a JSON-encoded string to the current object or array
      - pps_encoder_add_null()
        Add a null to the current object or array
      - pps_encoder_add_string()
        Add a string to the current object or array
      - pps_encoder_buffer()
        Return a pointer to the buffer holding the encoded data
      - pps_encoder_cleanup()
        Clean up an encoder structure, releasing any allocated memory
      - pps_encoder_clear_option()
        Disable an encoder option
      - pps_encoder_delete_attribute()
        Add an attribute and mark it as deleted
      - pps_encoder_end_array()
        End the current array
      - pps_encoder_end_object()
        End the current object
      - pps_encoder_error_t
        pps_encoder_error_t
      - pps_encoder_initialize()
        Initialize an encoder structure
      - pps_encoder_length()
        Return the length of the encoded data
      - pps_encoder_reset()
        Reset an encoder prior to encoding new data
      - pps_encoder_set_option()
        Enable an encoder option
      - pps_encoder_start_array()
        Start a new array
      - pps_encoder_start_object()
        Start a new object
      - pps_encoder_t
        Encoder structure
      - pps_node_type_t
        pps_node_type_t
      - pps_options_t
        PPS options
      - pps_status_t
        ppsparse() return values
      - ppsparse()
        Parse an object read from PPS
    - Examples
  - Platform-independent Publish/Subscribe Developer's Guide
    This guide is intended for application developers who want to use the Platform-independent Publish Subscribe (PiPS) framework to exchange information with other applications. First, the overall PiPS design and data-exchange model are explained. Then, tutorials on using PiPS are given. These tutorials cover key tasks such as selecting a publish-subscribe provider to use and writing plugins that read and write custom data types.
  - QDB Developer's Guide
  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SMMUMAN User's Guide
  - System Analysis Toolkit (SAT) User's Guide
  - System Architecture
    The System Architecture guide accompanies the QNX Neutrino RTOS and is intended for both application developers and end-users.
  - Technotes
  - User's Guide
    The QNX Neutrino User's Guide is intended for all users of a QNX Neutrino RTOS system, from system administrators to end users.
- Audio & Graphics API
- Multimedia
- Networking Middleware
- Programming
- Sensor Framework
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX Neutrino RTOS system and developers who want to create a QNX Neutrino resource manager free from vulnerabilities.
- Utilities & Libraries
QNX Hypervisor
The QNX Hypervisor allows you to run multiple OSs on a target system so you can separate critical and non-critical functions, support a wide variety of applications, and reduce hardware costs.
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX software in Amazon Web Services (AWS) and Microsoft Azure (Azure).
QNX Advanced Virtualization Frameworks User's Guide
This User's Guide is aimed at all systems integrators and developers who want to design and build embedded systems using the QNX Advanced Virtualization Frameworks.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

pps_decoder_pop()

Ascend to the parent of the current node

Synopsis:

#include <sys/pps.h>
            
pps_decoder_error_t pps_decoder_pop(pps_decoder_t *decoder);

Arguments:

decoder: A pointer to the PPS decoder structure.

Library:

libpps

Description:

The function pps_decoder_pop() ascends to the parent of the current object or array. Following this call, the current node will be the node that follows the object or array popped out of (that is, the sibling of the node that was current at the time this function was called).

Returns:

PPS_DECODER_OK: Success.
PPS_DECODER_POP_AT_ROOT: Already positioned at the root node.
>=1: An error occurred. See pps_decoder_error_t.

Classification:

QNX Neutrino


Safety:
Interrupt handler	No
Signal handler	No
Thread	Yes

Page updated: March 12, 2026