Documented APIs: tracefs_instance_get_name() tracefs_instances_walk() tracefs_instance_exists() Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx> --- Documentation/libtracefs-instances-utils.txt | 112 +++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 Documentation/libtracefs-instances-utils.txt diff --git a/Documentation/libtracefs-instances-utils.txt b/Documentation/libtracefs-instances-utils.txt new file mode 100644 index 0000000..aa5efbd --- /dev/null +++ b/Documentation/libtracefs-instances-utils.txt @@ -0,0 +1,112 @@ +libtracefs(3) +============= + +NAME +---- +tracefs_instance_get_name, tracefs_instances_walk, tracefs_instance_exists - +Helper functions for working with tracing instances. + +SYNOPSIS +-------- +[verse] +-- +*#include <tracefs.h>* + +const char pass:[*]*tracefs_instance_get_name*(struct tracefs_instance pass:[*]_instance_); +int *tracefs_instances_walk*(int (pass:[*]_callback_)(const char pass:[*], void pass:[*]), void pass:[*]_context)_; +bool *tracefs_instance_exists*(const char pass:[*]_name_); + +-- + +DESCRIPTION +----------- +Helper functions for working with trace instances. + +The _tracefs_instance_get_name()_ function returns the name of the given _instance_. +Note that the top instance has no name, the function returns NULL for it. + +The _tracefs_instances_walk()_ function walks through all configured tracing +instances in the system and calls _callback_ for each one of them. The _context_ +argument is passed to the _callback_, together with the instance name. If the +_callback_ returns non-zero, the iteration stops. Note, the _callback_ is not +called for the top top instance. + +The _tracefs_instance_exists()_ function checks if an instance with the given +_name_ exists in the system. + +RETURN VALUE +------------ +The _tracefs_instance_get_name()_ returns a string or NULL in case of the top +instance. The returned string must _not_ be freed. + +The _tracefs_instances_walk()_ function returns 0, if all instances were iterated, 1 +if the iteration was stopped by the _callback_, or -1 in case of an error. + +The _tracefs_instance_exists()_ returns true if an instance with the given name +exists in the system or false otherwise. + +EXAMPLE +------- +[source,c] +-- +#include <tracefs.h> + +struct tracefs_instance *inst; +.... +char *name = tracefs_instance_get_name(inst); + + if(name) { + /* Got name of the instance */ + } + +... +static int instance_walk(char *name, void *context) +{ + /* Got instance with name */ + return 0; +} +... + if (tracefs_instances_walk(instance_walk, NULL) < 0) { + /* Error walking through the instances */ + } +... + if (tracefs_instance_exists("foo")) { + /* There is instance with name foo in the system */ + } else { + /* There is no instance with name foo in the system */ + } +-- +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