xref: /OK3568_Linux_fs/kernel/tools/lib/traceevent/Documentation/libtraceevent-event_get.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyunlibtraceevent(3)
2*4882a593Smuzhiyun================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunNAME
5*4882a593Smuzhiyun----
6*4882a593Smuzhiyuntep_get_event, tep_get_first_event, tep_get_events_count - Access events.
7*4882a593Smuzhiyun
8*4882a593SmuzhiyunSYNOPSIS
9*4882a593Smuzhiyun--------
10*4882a593Smuzhiyun[verse]
11*4882a593Smuzhiyun--
12*4882a593Smuzhiyun*#include <event-parse.h>*
13*4882a593Smuzhiyun
14*4882a593Smuzhiyunstruct tep_event pass:[*]*tep_get_event*(struct tep_handle pass:[*]_tep_, int _index_);
15*4882a593Smuzhiyunstruct tep_event pass:[*]*tep_get_first_event*(struct tep_handle pass:[*]_tep_);
16*4882a593Smuzhiyunint *tep_get_events_count*(struct tep_handle pass:[*]_tep_);
17*4882a593Smuzhiyun--
18*4882a593Smuzhiyun
19*4882a593SmuzhiyunDESCRIPTION
20*4882a593Smuzhiyun-----------
21*4882a593SmuzhiyunThe _tep_get_event()_ function returns a pointer to event at the given _index_.
22*4882a593SmuzhiyunThe _tep_ argument is trace event parser context, the _index_ is the index of
23*4882a593Smuzhiyunthe requested event.
24*4882a593Smuzhiyun
25*4882a593SmuzhiyunThe _tep_get_first_event()_ function returns a pointer to the first event.
26*4882a593SmuzhiyunAs events are stored in an array, this function returns the pointer to the
27*4882a593Smuzhiyunbeginning of the array. The _tep_ argument is trace event parser context.
28*4882a593Smuzhiyun
29*4882a593SmuzhiyunThe _tep_get_events_count()_ function returns the number of the events
30*4882a593Smuzhiyunin the array. The _tep_ argument is trace event parser context.
31*4882a593Smuzhiyun
32*4882a593SmuzhiyunRETURN VALUE
33*4882a593Smuzhiyun------------
34*4882a593SmuzhiyunThe _tep_get_event()_ returns a pointer to the event located at _index_.
35*4882a593SmuzhiyunNULL is returned in case of error, in case there are no events or _index_ is
36*4882a593Smuzhiyunout of range.
37*4882a593Smuzhiyun
38*4882a593SmuzhiyunThe _tep_get_first_event()_ returns a pointer to the first event. NULL is
39*4882a593Smuzhiyunreturned in case of error, or in case there are no events.
40*4882a593Smuzhiyun
41*4882a593SmuzhiyunThe _tep_get_events_count()_ returns the number of the events. 0 is
42*4882a593Smuzhiyunreturned in case of error, or in case there are no events.
43*4882a593Smuzhiyun
44*4882a593SmuzhiyunEXAMPLE
45*4882a593Smuzhiyun-------
46*4882a593Smuzhiyun[source,c]
47*4882a593Smuzhiyun--
48*4882a593Smuzhiyun#include <event-parse.h>
49*4882a593Smuzhiyun...
50*4882a593Smuzhiyunstruct tep_handle *tep = tep_alloc();
51*4882a593Smuzhiyun...
52*4882a593Smuzhiyunint i,count = tep_get_events_count(tep);
53*4882a593Smuzhiyunstruct tep_event *event, *events = tep_get_first_event(tep);
54*4882a593Smuzhiyun
55*4882a593Smuzhiyunif (events == NULL) {
56*4882a593Smuzhiyun	/* There are no events */
57*4882a593Smuzhiyun} else {
58*4882a593Smuzhiyun	for (i = 0; i < count; i++) {
59*4882a593Smuzhiyun		event = (events+i);
60*4882a593Smuzhiyun		/* process events[i] */
61*4882a593Smuzhiyun	}
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun	/* Get the last event */
64*4882a593Smuzhiyun	event = tep_get_event(tep, count-1);
65*4882a593Smuzhiyun}
66*4882a593Smuzhiyun--
67*4882a593Smuzhiyun
68*4882a593SmuzhiyunFILES
69*4882a593Smuzhiyun-----
70*4882a593Smuzhiyun[verse]
71*4882a593Smuzhiyun--
72*4882a593Smuzhiyun*event-parse.h*
73*4882a593Smuzhiyun	Header file to include in order to have access to the library APIs.
74*4882a593Smuzhiyun*-ltraceevent*
75*4882a593Smuzhiyun	Linker switch to add when building a program that uses the library.
76*4882a593Smuzhiyun--
77*4882a593Smuzhiyun
78*4882a593SmuzhiyunSEE ALSO
79*4882a593Smuzhiyun--------
80*4882a593Smuzhiyun_libtraceevent(3)_, _trace-cmd(1)_
81*4882a593Smuzhiyun
82*4882a593SmuzhiyunAUTHOR
83*4882a593Smuzhiyun------
84*4882a593Smuzhiyun[verse]
85*4882a593Smuzhiyun--
86*4882a593Smuzhiyun*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*.
87*4882a593Smuzhiyun*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page.
88*4882a593Smuzhiyun--
89*4882a593SmuzhiyunREPORTING BUGS
90*4882a593Smuzhiyun--------------
91*4882a593SmuzhiyunReport bugs to  <linux-trace-devel@vger.kernel.org>
92*4882a593Smuzhiyun
93*4882a593SmuzhiyunLICENSE
94*4882a593Smuzhiyun-------
95*4882a593Smuzhiyunlibtraceevent is Free Software licensed under the GNU LGPL 2.1
96*4882a593Smuzhiyun
97*4882a593SmuzhiyunRESOURCES
98*4882a593Smuzhiyun---------
99*4882a593Smuzhiyunhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
100