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1 | --- |
2 | id: assigning-log-levels | |
3 | --- | |
4 | ||
5 | Optionally, a log level can be assigned to a defined tracepoint. | |
6 | Assigning different levels of importance to tracepoints can be useful; | |
7 | when controlling tracing sessions, | |
8 | [you can choose](#doc-controlling-tracing) to only enable tracepoints | |
9 | falling into a specific log level range. | |
10 | ||
11 | Log levels are assigned to defined tracepoints using the | |
12 | `TRACEPOINT_LOGLEVEL()` macro. The latter must be used _after_ having | |
13 | used `TRACEPOINT_EVENT()` for a given tracepoint. The | |
14 | `TRACEPOINT_LOGLEVEL()` macro has the following construct: | |
15 | ||
16 | ~~~ c | |
17 | TRACEPOINT_LOGLEVEL(<provider name>, <tracepoint name>, <log level>) | |
18 | ~~~ | |
19 | ||
20 | where the first two arguments are the same as the first two arguments | |
21 | of `TRACEPOINT_EVENT()` and `<log level>` is one | |
22 | of the values given in the | |
23 | [LTTng-UST library reference](#doc-liblttng-ust-tracepoint-loglevel) | |
24 | section. | |
25 | ||
26 | As an example, let's assign a `TRACE_DEBUG_UNIT` log level to our | |
27 | previous tracepoint definition: | |
28 | ||
29 | ~~~ c | |
30 | TRACEPOINT_LOGLEVEL(my_provider, my_tracepoint, TRACE_DEBUG_UNIT) | |
31 | ~~~ |