aboutsummaryrefslogtreecommitdiffstats
path: root/tools/lib/traceevent/Documentation/libtraceevent-host_endian.txt
blob: d5d375eb8d1e934037891b1bdef27214a776adaf (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
libtraceevent(3)
================

NAME
----
tep_is_bigendian, tep_is_local_bigendian, tep_set_local_bigendian - Get / set
the endianness of the local machine.

SYNOPSIS
--------
[verse]
--
*#include <event-parse.h>*

enum *tep_endian* {
	TEP_LITTLE_ENDIAN = 0,
	TEP_BIG_ENDIAN
};

int *tep_is_bigendian*(void);
bool *tep_is_local_bigendian*(struct tep_handle pass:[*]_tep_);
void *tep_set_local_bigendian*(struct tep_handle pass:[*]_tep_, enum tep_endian _endian_);
--

DESCRIPTION
-----------

The _tep_is_bigendian()_ gets the endianness of the machine, executing
the function.

The _tep_is_local_bigendian()_ function gets the endianness of the local
machine, saved in the _tep_ handler. The _tep_ argument is the trace event
parser context. This API is a bit faster than _tep_is_bigendian()_, as it
returns cached endianness of the local machine instead of checking it each time.

The _tep_set_local_bigendian()_ function sets the endianness of the local
machine in the _tep_ handler. The _tep_ argument is trace event parser context.
The _endian_ argument is the endianness:
[verse]
--
	_TEP_LITTLE_ENDIAN_ - the machine is little endian,
	_TEP_BIG_ENDIAN_ - the machine is big endian.
--

RETURN VALUE
------------
The _tep_is_bigendian()_ function returns non zero if the endianness of the
machine, executing the code, is big endian and zero otherwise.

The _tep_is_local_bigendian()_ function returns true, if the endianness of the
local machine, saved in the _tep_ handler, is big endian, or false otherwise.

EXAMPLE
-------
[source,c]
--
#include <event-parse.h>
...
struct tep_handle *tep = tep_alloc();
...
	if (tep_is_bigendian())
		tep_set_local_bigendian(tep, TEP_BIG_ENDIAN);
	else
		tep_set_local_bigendian(tep, TEP_LITTLE_ENDIAN);
...
	if (tep_is_local_bigendian(tep))
		printf("This machine you are running on is bigendian\n");
	else
		printf("This machine you are running on is little endian\n");

--

FILES
-----
[verse]
--
*event-parse.h*
	Header file to include in order to have access to the library APIs.
*-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