The Messaging API for C (also referred to as SolClient) is specifically designed to provide high message throughput and low latency with the lowest CPU utilization possible. In addition to the common Enterprise API features, the C API enables fine-grained control of threading and message processing through additional features like:

  • Allows fine-tuning of API behavior, such as whether operations should be blocking or non-blocking in nature.
  • Allows for the option of application file descriptors to be monitored within the API, providing the application with callbacks for readable and writable events.
  • Allows for the option of the application taking over control of file descriptors created within the API to connect to event brokers, where the application must provide readable and writable events to the API.
  • Support for timer services.

Message Exchange Patterns

The C API supports all common message exchange patterns.

  • Publish / Subscribe
  • Point-to-Point
  • Request / Reply

For more information, see Message Exchange Patterns.


The C API supports:

  • Connection management to Solace PubSub+ event brokers
  • Addition and removal of topic subscriptions
  • Sending and receiving messages Direct and Guaranteed messages
  • Structured data types that do not rely on a specific architecture or programming language
  • Extensive support for logging and customizing through property parameters
  • Request/reply messaging support
  • Session Transactions
  • PubSub+ Cache Client API support
  • Queue browsing
  • Topic dispatch
  • Message Replay
  • Provisioning of durable endpoints

The C API does not currently support the following features.

  • XA Transactions

Get Started

These tutorials introduce you to developing applications using the C API, and will get you up-to-speed and sending messages with Solace technology as quickly as possible. They cover common messaging requirements such as pub/sub.

There are three ways you can get started:

  1. If you have Solace PubSub+ event brokers already deployed, obtain the hostname, or IP address, of an event broker to test against, a username and password to access it, and a Message VPN in which you can produce and consume messages.
  2. You can go through an Initial Set Up of a software event broker.
  3. You can spin up Solace PubSub+ Cloud.

Start Tutorials

C API Reference

Click below to access the developer reference for the Solace C API.

C API Reference

C API Release Notes

Click below to download the latest release notes for the Solace C API.

C API Release Notes