Solace C++ Publisher & Subscriber

A minimal, self‑contained example demonstrating how to build a C++ publisher and subscriber using the Solace C API (solclient). The subscriber listens on the topic fx/rates/normalized, and the publisher sends a sample FX payload (EURUSD=1.1034) to the same topic.

Overview

This project contains two standalone executables:

subscriber — connects to Solace, subscribes to a topic, and prints received messages

publisher — connects to Solace and publishes a binary‑attachment message to a topic

Both programs use:

solClient_initialize for API setup

context with internal I/O thread

callbacks for events and messages

binary attachment payloads

topic-based publish/subscribe

Requirements

Solace PubSub+ Broker (local or remote) , I have setup on Docker on Mac

Solace C API (solclient) installed (Be sure about the api version and compatibility, this is tested with solclient_Darwin-universal2_opt_7.33.1.1 )

C++ compiler (g++/clang++) Linux or WSL recommended . ├── README.md ├── publisher.cpp └── subscriber.cpp

Build Instructions

1. Set Solace library paths Example (adjust to your installation): export LD_LIBRARY_PATH=/usr/sw/solclient/lib:$LD_LIBRARY_PATH export CPATH=/usr/sw/solclient/include

2. Compile subscriber bash gclang++ subscriber.cpp -std=c++20 \ -I /Users/$USER/solace-c/include
   -L /Users/$USER/solace-c/lib
   -lsolclient
   -Wl,-rpath,/Users/$USER/solace-c/lib
   -o subscriber

3. Compile publisher clang++ publisher.cpp -std=c++20 \ -I /Users/$USER/solace-c/include
   -L /Users/$USER/solace-c/lib
   -lsolclient
   -Wl,-rpath,/Users/$USER/solace-c/lib
   -o publisher

Running the Programs

1. Start the subscriber bash ./subscriber You should see:

Output: ./subscriber Initializing Solace API... solClient_initialize rc = 0 context_create rc = 0 session_create rc = 0 session pointer = 0x4000ffe [Event] Session up session_connect rc = 0 topicSubscribe rc = 0 Listening on topic fx/rates/normalized...

2. Run the publisher bash ./publisher

Output: ./publisher Connected. Publishing messages... Message sent: EURUSD=1.1034

3. Subscriber output

[Callback] messageCallback fired [Message] Received: EURUSD=1.1034

Solace Queue

Solace Topic

How It Works

Subscriber Initializes Solace API

Creates a context with an internal thread

Creates a session with message + event callbacks

Subscribes to topic fx/rates/normalized

Prints incoming binary payloads

Publisher Initializes API and creates session

Allocates a message

Sets topic destination

Attaches binary payload

Sends message via session

Notes

Queue subscriptions require Solace API 8.x+; this example uses topic subscription for compatibility.

The subscriber uses an internal Solace I/O thread, so no manual event loop is required.

Payloads are handled as binary attachments, which is the recommended pattern for raw text or encoded data.