NAME
----
-tracelog - LTTng-UST printf(3)-like interface with a log level
+tracelog, vtracelog - LTTng-UST printf(3)-like interface with a log level
SYNOPSIS
[verse]
#define *tracelog*('level', 'fmt', ...)
+#define *vtracelog*('level', 'fmt', 'ap')
-Link with `-llttng-ust`.
+Link with `-llttng-ust -llttng-ust-common`.
DESCRIPTION
-----------
-The LTTng-UST `tracelog()` API allows you to trace your application with
-the help of a simple man:printf(3)-like macro, with an additional
-parameter for the desired log level. The 'fmt' argument is passed
-directly to the 'fmt' parameter of man:vasprintf(3), as well as
-the optional parameters following 'fmt'.
+The `tracelog()` and `vtracelog()` macros are part of version{nbsp}0 of
+the LTTng-UST API (see the ``Compatibility with previous APIs'' section
+of man:lttng-ust(3)).
-The purpose of `tracelog()` is to ease the migration from logging to
-tracing.
-
-The available values for the 'level' parameter are:
-
-include::log-levels.txt[]
-
-To use `tracelog()`, include `<lttng/tracelog.h>` where you need it, and
-link your application with `liblttng-ust`. See the <<example,EXAMPLE>>
-section below for a complete usage example.
-
-Once your application is instrumented with `tracelog()` calls and
-ready to run, use man:lttng-enable-event(1) to enable the
-`lttng_ust_tracelog:*` event. You can isolate specific log levels with
-the nloption:--loglevel and nloption:--loglevel-only options of this
-command.
-
-The `tracelog()` events contain the following fields:
-
-[options="header"]
-|===
-|Field name |Description
-
-|`line`
-|Line in source file where `tracelog()` was called.
-
-|`file`
-|Source file from which `tracelog()` was called.
-
-|`func`
-|Function name from which `tracelog()` was called.
-
-|`msg`
-|Formatted string output.
-|===
-
-If you do not need to attach a specific log level to a `tracelog()`
-call, use man:tracef(3) instead.
-
-See also the <<limitations,LIMITATIONS>> section below for important
-limitations to consider when using `tracelog()`.
-
-
-[[example]]
-EXAMPLE
--------
-Here's a usage example of `tracelog()`:
-
--------------------------------------------------------------------
-#include <stdlib.h>
-#include <lttng/tracelog.h>
-
-int main(int argc, char *argv[])
-{
- int i;
-
- if (argc < 2) {
- tracelog(TRACE_CRIT, "Not enough arguments: %d", argc);
- return EXIT_FAILURE;
- }
-
- tracelog(TRACE_INFO, "Starting app with %d arguments", argc);
-
- for (i = 0; i < argc; i++) {
- tracelog(TRACE_DEBUG, "Argument %d: %s", i, argv[i]);
- }
-
- tracelog(TRACE_INFO, "Exiting app");
-
- return EXIT_SUCCESS;
-}
--------------------------------------------------------------------
-
-This C source file, saved as `app.c`, can be compiled into a program
-like this:
-
-[role="term"]
-----
-$ cc -o app app.c -llttng-ust
-----
-
-You can create an LTTng tracing session, enable all the `tracelog()`
-events, and start the created tracing session like this:
-
-[role="term"]
-----
-$ lttng create my-session
-$ lttng enable-event --userspace 'lttng_ust_tracelog:*'
-$ lttng start
-----
-
-Or you can enable `tracelog()` events matching a log level at least
-as severe as a given log level:
-
-[role="term"]
-----
-$ lttng enable-event --userspace 'lttng_ust_tracelog:*' \
- --loglevel=TRACE_INFO
-----
-
-Next, start the program to be traced:
-
-[role="term"]
-----
-$ ./app a few arguments passed to this application
-----
-
-Finally, stop the tracing session, and inspect the recorded events:
-
-[role="term"]
-----
-$ lttng stop
-$ lttng view
-----
-
-
-[[limitations]]
-LIMITATIONS
------------
-:macro-name: tracelog
-
-include::tracef-tracelog-limitations.txt[]
+Prefer using man:lttng_ust_tracelog(3) and man:lttng_ust_vtracelog(3)
+which are part of version{nbsp}1 of the API and have the `lttng_ust_`
+namespace.
include::common-footer.txt[]
SEE ALSO
--------
-man:tracef(3),
-man:lttng-ust(3),
-man:lttng(1),
-man:printf(3)
+man:lttng_ust_tracelog(3),
+man:lttng_ust_vtracelog(3)
projects / lttng-ust.git / blobdiff