Enable distributed tracing for your C applications

Read on to learn how to enable and instrument distributed tracing for the New Relic's C SDK.

Enable distributed tracing

To enable distributed tracing for a New Relic-monitored C application:

Create a default newrelic_app_config_t and set the distributed_tracing.enabled field to true.
```
newrelic_app_config_t* config
    = newrelic_create_app_config(app_name, license_key);
config->distributed_tracing.enabled = true;
```
Continue with the procedures to instrument transactions and HTTP requests.

Important

Span events can be enabled/disabled separately from distributed tracing.

Instrument transactions and HTTP requests

For transactions that occur in multiple services, the distributed trace payload contains information that allows New Relic to stitch them together into a complete transaction trace. However, if New Relic-monitored services are not sending trace context to each other, it will result in incomplete trace details. For more information, see the documentation about passing the distributed tracing API header and the C SDK's distributed tracing documentation on GitHub.

If you want to...	Use this
Create and return a payload to be sent to the called service	`newrelic_create_distributed_trace_payload()`
Accept a payload sent from the first service	`newrelic_accept_distributed_trace_payload()` This will link these services together in a trace.
Return a base64-encoded JSON string representation of the payload	`newrelic_create_distributed_trace_payload_httpsafe()` This offers the same behavior as `newrelic_create_distributed_trace_payload()`.
Accept a base64-encoded string for the payload	`newrelic_accept_distributed_trace_payload_httpsafe()` This offers the same behavior as `newrelic_accept_distributed_trace_payload()`.

For more help

If you need more help, check out these support and learning resources:

Browse the Explorers Hub to get help from the community and join in discussions.
Find answers on our sites and learn how to use our support portal.
Run New Relic Diagnostics, our troubleshooting tool for Linux, Windows, and macOS.
Review New Relic's data security and licenses documentation.

Enable distributed tracing for your C applications