[v2,8/8] libtracefs man pages: helper APIs for working with trace file system.

Commit Message

Tzvetomir Stoyanov (VMware) Dec. 21, 2020, 6:02 a.m. UTC

Documented APIs:
tracefs_tracers()
tracefs_get_clock()
tracefs_list_free()

Signed-off-by: Tzvetomir Stoyanov (VMware) <[e-mail]>
---
 Documentation/libtracefs-utils.txt | 103 +++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 Documentation/libtracefs-utils.txt

Comments

Steven Rostedt Dec. 21, 2020, 5:21 p.m. UTC | #1

On Mon, 21 Dec 2020 08:02:52 +0200
"Tzvetomir Stoyanov (VMware)" <[e-mail]> wrote:

> +DESCRIPTION
> +-----------
> +Various useful functions for working with trace file system.
> +
> +The _tracefs_tracers()_ function returns array of strings with the
> +names of supported tracer plugins, located in the given _tracing_dir_ directory.
> +This could be NULL or tracefs mount point, for trace systems in top instance,
> +or full path to a trace instance, for trace systems in that instance.
> +The last entry in the array as a NULL pointer. The array must
> +be freed with _tracefs_list_free()_ API.

The description above needs to be updated as well.

-- Steve

> +
> +The _tracefs_get_clock()_ function returns name of the current trace clock,
> +used in the given _instance_. If _instance_ is NULL, the clock of the main
> +trace instance is returned. The returned string must be freed with free().
> +
> +The _tracefs_list_free()_ function frees an array of strings, returned by
> +_tracefs_event_systems()_, _tracefs_system_events()_ and _tracefs_tracers()_
> +APIs.
> +

Patch

diff --git a/Documentation/libtracefs-utils.txt b/Documentation/libtracefs-utils.txt
new file mode 100644
index 0000000..86dd754
--- /dev/null
+++ b/Documentation/libtracefs-utils.txt
@@ -0,0 +1,103 @@ 
+libtracefs(3)
+=============
+
+NAME
+----
+tracefs_tracers, tracefs_get_clock, tracefs_list_free -
+Helper functions for working with trace file system.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <tracefs.h>*
+
+char pass:[*]pass:[*]*tracefs_tracers*(const char pass:[*]_tracing_dir_);
+char pass:[*]*tracefs_get_clock*(struct tracefs_instance pass:[*]_instance_);
+void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
+--
+
+DESCRIPTION
+-----------
+Various useful functions for working with trace file system.
+
+The _tracefs_tracers()_ function returns array of strings with the
+names of supported tracer plugins, located in the given _tracing_dir_ directory.
+This could be NULL or tracefs mount point, for trace systems in top instance,
+or full path to a trace instance, for trace systems in that instance.
+The last entry in the array as a NULL pointer. The array must
+be freed with _tracefs_list_free()_ API.
+
+The _tracefs_get_clock()_ function returns name of the current trace clock,
+used in the given _instance_. If _instance_ is NULL, the clock of the main
+trace instance is returned. The returned string must be freed with free().
+
+The _tracefs_list_free()_ function frees an array of strings, returned by
+_tracefs_event_systems()_, _tracefs_system_events()_ and _tracefs_tracers()_
+APIs.
+
+RETURN VALUE
+------------
+The _tracefs_tracers()_ returns array of strings. The last element in that
+array is a NULL pointer. The array must be freed with _tracefs_list_free()_ API.
+In case of an error, NULL is returned.
+
+The _tracefs_get_clock()_ returns string, that must be freed with free(), or NULL
+in case of an error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <tracefs.h>
+
+char **tracers = tracefs_tracers(NULL);
+
+	if (tracers) {
+		/* Got tracer plugins from the top trace instance */
+		...
+		tracefs_list_free(tracers);
+	}
+....
+char *clock = tracefs_get_clock(NULL);
+
+	if (clock) {
+		/* Got current trace clock of the top trace instance */
+		...
+		free(clock);
+	}
+--
+FILES
+-----
+[verse]
+--
+*tracefs.h*
+	Header file to include in order to have access to the library APIs.
+*-ltracefs*
+	Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtracefs(3)_,
+_libtraceevent(3)_,
+_trace-cmd(1)_
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <[e-mail]>
+*Tzvetomir Stoyanov* <[e-mail]>
+--
+REPORTING BUGS
+--------------
+Report bugs to  <[e-mail]>
+
+LICENSE
+-------
+libtracefs is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
\ No newline at end of file