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Diffstat (limited to 'tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt')
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1 files changed, 0 insertions, 156 deletions
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt b/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt deleted file mode 100644 index 53d37d72a1c1..000000000000 --- a/tools/lib/traceevent/Documentation/libtraceevent-reg_event_handler.txt +++ /dev/null @@ -1,156 +0,0 @@ -libtraceevent(3) -================ - -NAME ----- -tep_register_event_handler, tep_unregister_event_handler - Register / -unregisters a callback function to parse an event information. - -SYNOPSIS --------- -[verse] --- -*#include <event-parse.h>* - -enum *tep_reg_handler* { - _TEP_REGISTER_SUCCESS_, - _TEP_REGISTER_SUCCESS_OVERWRITE_, -}; - -int *tep_register_event_handler*(struct tep_handle pass:[*]_tep_, int _id_, const char pass:[*]_sys_name_, const char pass:[*]_event_name_, tep_event_handler_func _func_, void pass:[*]_context_); -int *tep_unregister_event_handler*(struct tep_handle pass:[*]tep, int id, const char pass:[*]sys_name, const char pass:[*]event_name, tep_event_handler_func func, void pass:[*]_context_); - -typedef int (*pass:[*]tep_event_handler_func*)(struct trace_seq pass:[*]s, struct tep_record pass:[*]record, struct tep_event pass:[*]event, void pass:[*]context); --- - -DESCRIPTION ------------ -The _tep_register_event_handler()_ function registers a handler function, -which is going to be called to parse the information for a given event. -The _tep_ argument is the trace event parser context. The _id_ argument is -the id of the event. The _sys_name_ argument is the name of the system, -the event belongs to. The _event_name_ argument is the name of the event. -If _id_ is >= 0, it is used to find the event, otherwise _sys_name_ and -_event_name_ are used. The _func_ is a pointer to the function, which is going -to be called to parse the event information. The _context_ argument is a pointer -to the context data, which will be passed to the _func_. If a handler function -for the same event is already registered, it will be overridden with the new -one. This mechanism allows a developer to override the parsing of a given event. -If for some reason the default print format is not sufficient, the developer -can register a function for an event to be used to parse the data instead. - -The _tep_unregister_event_handler()_ function unregisters the handler function, -previously registered with _tep_register_event_handler()_. The _tep_ argument -is the trace event parser context. The _id_, _sys_name_, _event_name_, _func_, -and _context_ are the same arguments, as when the callback function _func_ was -registered. - -The _tep_event_handler_func_ is the type of the custom event handler -function. The _s_ argument is the trace sequence, it can be used to create a -custom string, describing the event. A _record_ to get the event from is passed -as input parameter and also the _event_ - the handle to the record's event. The -_context_ is custom context, set when the custom event handler is registered. - -RETURN VALUE ------------- -The _tep_register_event_handler()_ function returns _TEP_REGISTER_SUCCESS_ -if the new handler is registered successfully or -_TEP_REGISTER_SUCCESS_OVERWRITE_ if an existing handler is overwritten. -If there is not enough memory to complete the registration, -TEP_ERRNO__MEM_ALLOC_FAILED is returned. - -The _tep_unregister_event_handler()_ function returns 0 if _func_ was removed -successful or, -1 if the event was not found. - -The _tep_event_handler_func_ should return -1 in case of an error, -or 0 otherwise. - -EXAMPLE -------- -[source,c] --- -#include <event-parse.h> -#include <trace-seq.h> -... -struct tep_handle *tep = tep_alloc(); -... -int timer_expire_handler(struct trace_seq *s, struct tep_record *record, - struct tep_event *event, void *context) -{ - trace_seq_printf(s, "hrtimer="); - - if (tep_print_num_field(s, "0x%llx", event, "timer", record, 0) == -1) - tep_print_num_field(s, "0x%llx", event, "hrtimer", record, 1); - - trace_seq_printf(s, " now="); - - tep_print_num_field(s, "%llu", event, "now", record, 1); - - tep_print_func_field(s, " function=%s", event, "function", record, 0); - - return 0; -} -... - int ret; - - ret = tep_register_event_handler(tep, -1, "timer", "hrtimer_expire_entry", - timer_expire_handler, NULL); - if (ret < 0) { - char buf[32]; - - tep_strerror(tep, ret, buf, 32) - printf("Failed to register handler for hrtimer_expire_entry: %s\n", buf); - } else { - switch (ret) { - case TEP_REGISTER_SUCCESS: - printf ("Registered handler for hrtimer_expire_entry\n"); - break; - case TEP_REGISTER_SUCCESS_OVERWRITE: - printf ("Overwrote handler for hrtimer_expire_entry\n"); - break; - } - } -... - ret = tep_unregister_event_handler(tep, -1, "timer", "hrtimer_expire_entry", - timer_expire_handler, NULL); - if ( ret ) - printf ("Failed to unregister handler for hrtimer_expire_entry\n"); - --- - -FILES ------ -[verse] --- -*event-parse.h* - Header file to include in order to have access to the library APIs. -*trace-seq.h* - Header file to include in order to have access to trace sequences - related APIs. Trace sequences are used to allow a function to call - several other functions to create a string of data to use. -*-ltraceevent* - Linker switch to add when building a program that uses the library. --- - -SEE ALSO --------- -_libtraceevent(3)_, _trace-cmd(1)_ - -AUTHOR ------- -[verse] --- -*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. -*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. --- -REPORTING BUGS --------------- -Report bugs to <linux-trace-devel@vger.kernel.org> - -LICENSE -------- -libtraceevent is Free Software licensed under the GNU LGPL 2.1 - -RESOURCES ---------- -https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git |