xref: /OK3568_Linux_fs/kernel/tools/lib/traceevent/Documentation/libtraceevent-handle.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyunlibtraceevent(3)
2*4882a593Smuzhiyun================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunNAME
5*4882a593Smuzhiyun----
6*4882a593Smuzhiyuntep_alloc, tep_free,tep_ref, tep_unref,tep_get_ref - Create, destroy, manage
7*4882a593Smuzhiyunreferences of trace event parser context.
8*4882a593Smuzhiyun
9*4882a593SmuzhiyunSYNOPSIS
10*4882a593Smuzhiyun--------
11*4882a593Smuzhiyun[verse]
12*4882a593Smuzhiyun--
13*4882a593Smuzhiyun*#include <event-parse.h>*
14*4882a593Smuzhiyun
15*4882a593Smuzhiyunstruct tep_handle pass:[*]*tep_alloc*(void);
16*4882a593Smuzhiyunvoid *tep_free*(struct tep_handle pass:[*]_tep_);
17*4882a593Smuzhiyunvoid *tep_ref*(struct tep_handle pass:[*]_tep_);
18*4882a593Smuzhiyunvoid *tep_unref*(struct tep_handle pass:[*]_tep_);
19*4882a593Smuzhiyunint *tep_get_ref*(struct tep_handle pass:[*]_tep_);
20*4882a593Smuzhiyun--
21*4882a593Smuzhiyun
22*4882a593SmuzhiyunDESCRIPTION
23*4882a593Smuzhiyun-----------
24*4882a593SmuzhiyunThese are the main functions to create and destroy tep_handle - the main
25*4882a593Smuzhiyunstructure, representing the trace event parser context. This context is used as
26*4882a593Smuzhiyunthe input parameter of most library APIs.
27*4882a593Smuzhiyun
28*4882a593SmuzhiyunThe _tep_alloc()_ function allocates and initializes the tep context.
29*4882a593Smuzhiyun
30*4882a593SmuzhiyunThe _tep_free()_ function will decrement the reference of the _tep_ handler.
31*4882a593SmuzhiyunWhen there is no more references, then it will free the handler, as well
32*4882a593Smuzhiyunas clean up all its resources that it had used. The argument _tep_ is
33*4882a593Smuzhiyunthe pointer to the trace event parser context.
34*4882a593Smuzhiyun
35*4882a593SmuzhiyunThe _tep_ref()_ function adds a reference to the _tep_ handler.
36*4882a593Smuzhiyun
37*4882a593SmuzhiyunThe _tep_unref()_ function removes a reference from the _tep_ handler. When
38*4882a593Smuzhiyunthe last reference is removed, the _tep_ is destroyed, and all resources that
39*4882a593Smuzhiyunit had used are cleaned up.
40*4882a593Smuzhiyun
41*4882a593SmuzhiyunThe _tep_ref_get()_ functions gets the current references of the _tep_ handler.
42*4882a593Smuzhiyun
43*4882a593SmuzhiyunRETURN VALUE
44*4882a593Smuzhiyun------------
45*4882a593Smuzhiyun_tep_alloc()_ returns a pointer to a newly created tep_handle structure.
46*4882a593SmuzhiyunNULL is returned in case there is not enough free memory to allocate it.
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun_tep_ref_get()_ returns the current references of _tep_.
49*4882a593SmuzhiyunIf _tep_ is NULL, 0 is returned.
50*4882a593Smuzhiyun
51*4882a593SmuzhiyunEXAMPLE
52*4882a593Smuzhiyun-------
53*4882a593Smuzhiyun[source,c]
54*4882a593Smuzhiyun--
55*4882a593Smuzhiyun#include <event-parse.h>
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun...
58*4882a593Smuzhiyunstruct tep_handle *tep = tep_alloc();
59*4882a593Smuzhiyun...
60*4882a593Smuzhiyunint ref = tep_get_ref(tep);
61*4882a593Smuzhiyuntep_ref(tep);
62*4882a593Smuzhiyunif ( (ref+1) != tep_get_ref(tep)) {
63*4882a593Smuzhiyun	/* Something wrong happened, the counter is not incremented by 1 */
64*4882a593Smuzhiyun}
65*4882a593Smuzhiyuntep_unref(tep);
66*4882a593Smuzhiyun...
67*4882a593Smuzhiyuntep_free(tep);
68*4882a593Smuzhiyun...
69*4882a593Smuzhiyun--
70*4882a593SmuzhiyunFILES
71*4882a593Smuzhiyun-----
72*4882a593Smuzhiyun[verse]
73*4882a593Smuzhiyun--
74*4882a593Smuzhiyun*event-parse.h*
75*4882a593Smuzhiyun	Header file to include in order to have access to the library APIs.
76*4882a593Smuzhiyun*-ltraceevent*
77*4882a593Smuzhiyun	Linker switch to add when building a program that uses the library.
78*4882a593Smuzhiyun--
79*4882a593Smuzhiyun
80*4882a593SmuzhiyunSEE ALSO
81*4882a593Smuzhiyun--------
82*4882a593Smuzhiyun_libtraceevent(3)_, _trace-cmd(1)_
83*4882a593Smuzhiyun
84*4882a593SmuzhiyunAUTHOR
85*4882a593Smuzhiyun------
86*4882a593Smuzhiyun[verse]
87*4882a593Smuzhiyun--
88*4882a593Smuzhiyun*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*.
89*4882a593Smuzhiyun*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page.
90*4882a593Smuzhiyun--
91*4882a593SmuzhiyunREPORTING BUGS
92*4882a593Smuzhiyun--------------
93*4882a593SmuzhiyunReport bugs to  <linux-trace-devel@vger.kernel.org>
94*4882a593Smuzhiyun
95*4882a593SmuzhiyunLICENSE
96*4882a593Smuzhiyun-------
97*4882a593Smuzhiyunlibtraceevent is Free Software licensed under the GNU LGPL 2.1
98*4882a593Smuzhiyun
99*4882a593SmuzhiyunRESOURCES
100*4882a593Smuzhiyun---------
101*4882a593Smuzhiyunhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
102