Documented APIs: tracefs_tracers() tracefs_get_clock() tracefs_list_free() Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> --- Documentation/libtracefs-utils.txt | 103 +++++++++++++++++++++++++++++ 1 file changed, 103 insertions(+) create mode 100644 Documentation/libtracefs-utils.txt diff --git a/Documentation/libtracefs-utils.txt b/Documentation/libtracefs-utils.txt new file mode 100644 index 0000000..03bc39b --- /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 the location of the tracefs mount point +for the trace systems of the local machine, or it may be a path to a copy +of the tracefs directory from another machine. 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* <rostedt@xxxxxxxxxxx> +*Tzvetomir Stoyanov* <tz.stoyanov@xxxxxxxxx> +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx> + +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 -- 2.28.0