Introduction to the C SDK | New Relic Documentation

EOL NOTICE

As of April 2022, we're discontinuing support for several capabilities, including the C SDK. Please explore the option to use OpenTelemetry as an alternative to send C++ telemetry data to New Relic. For more details about the EOL, see our Explorers Hub post.

The C SDK is designed to support the often complex, multi-threaded nature of C/C++ applications. You can gain a new level of visibility to help you identify and solve performance issues. You can also collect and analyze data to help you improve the customer experience and make data-driven business decisions.

The C SDK can be used to instrument a wide range of applications beyond C or C++. If your application does not use other languages supported by New Relic and can import C libraries, then you can use the New Relic C SDK to take advantage of our monitoring capabilities and features.

Start monitoring your C application

To use our C SDK agent:

Make sure your application meets the compatibility and requirements for the C SDK.
If you do not already have one, sign up for a free New Relic account.
Use our launcher, or follow the installation and instrumentation procedures to install the agent. Within a few minutes, you will be able to view data from your application in your New Relic account's UI.

Read the install docs

Add C data

Monitor app performance

one.newrelic.com > APM > (select an app): Here is an example of some of the data you can view in New Relic after you deploy the C SDK for your app.

If your app meets the C SDK's compatibility and requirements in Linux environments, you can customize the generic library to communicate with New Relic, then start with APM to monitor your app's performance.

What you can do	How to do it
See the big picture	Start with the APM Summary page to monitor the throughput, response times, errors, memory and CPU usage transactions in your applications and services, then explore other details with additional APM dashboards. With deployment markers, see how code changes impact application performance and health. Use infrastructure monitoring to view detailed host and server data. When you install the infrastructure agent and APM on the same host, they automatically detect one another. You can then view a list of hosts in the APM UI, and filter your Infrastructure hosts by app in the Infrastructure UI.
Identify and fix errors	Use error analytics tools to find bottlenecks by seeing time spent on database calls, external system calls, and key blocks of code. Get alert notifications for problems or errors before they affect users. Create custom dashboards for important metrics.
View logs for your APM and infrastructure data	You can bring your logs and application's data together to make troubleshooting easier and faster. No need to switch to another UI page. With logs in context, you can see log messages related to your errors and traces directly in your app's UI. You can also see logs in context of your infrastructure data, such as Kubernetes clusters.
Analyze business data	Query user-related data and improve business processes. Send your own custom data to New Relic. Create custom queries of your application data. Create and share visual, interactive displays of your data.
And more!	Monitor and troubleshoot your application users' desktop experience with your application, including page load timing problems, JavaScript errors, session trace timelines, etc., by using browser monitoring. Use automated, scriptable tools to monitor your websites, critical business transactions, and API endpoints with synthetic monitoring. Analyze and fine-tune your Android and iOS application performance, troubleshoot crashes, compare multiple versions, and examine the performance of HTTP and other network components with mobile monitoring.

Architecture: C library and daemon

The C SDK relies on two components to send data from your application to New Relic:

The lC SDK calls: You download this library, then add the calls and instrumentation to your application's code. This allows you to identify and customize the kinds of data that matters the most to you.
The C SDK daemon: This is a separate binary that accumulates data from the C SDK calls, and sends it to New Relic. This acts as a proxy between the SDK and New Relic.

C SDK architecture: To send data from your application to New Relic, the daemon must be invoked before making calls to your application's C SDK instrumentation library.

Working together, the C SDK instrumentation and the daemon forward data on to New Relic where you can view and query data about transactions. The workflow between your application and New Relic must occur in this order:

An HTTPS link is established between the daemon and New Relic. The daemon must be invoked first, before your instrumented application is invoked.
Next, socket communication is established between your instrumented application and the daemon. This occurs after successful calls to newrelic_new_app_config() and newrelic_create_app().

The call to newrelic_create_app() is non-blocking. Its second parameter allows you to specify an amount of time for your instrumented application to wait so that the socket communication is adequately established. For example:

newrelic_app_t* app = newrelic_create_app(config, 10000);

If your instrumented application sends transactions before both the daemon connection and your application's socket communication are established, data reported from your application will be lost.

Check the source code

The C SDK is open source software. That means you can browse its source code and send improvements, or create your own fork and build it. For more information, see the README.