[v4,17/46] tools/lib/traceevent: Man page for tep_read_number()

Commit Message

Tzvetomir Stoyanov March 8, 2019, 1:36 p.m. UTC

Create man page for tep_read_number() as part of the libtraceevent APIs.

Signed-off-by: Tzvetomir Stoyanov <[e-mail]>
---
 .../libtraceevent-endian_read.txt             | 76 +++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-endian_read.txt

Comments

Steven Rostedt March 13, 2019, 5:26 p.m. UTC | #1

On Fri,  8 Mar 2019 15:36:25 +0200
Tzvetomir Stoyanov <[e-mail]> wrote:

> +struct tep_handle *tep = tep_alloc();
> +...
> +void process_record(struct tep_record *record)
> +{
> +	int data = tep_read_number(tep, record->data, 4);
> +	/* Read the first 4 bytes of the record as integer */

I would use a better example like:

	int offset = 24;
	int data = tep_read_number(tep, record->data + offset, 4);

	/* Read the 4 bytes at the offset 24 of data as an integer */

-- Steve

> +}

Patch

diff --git a/tools/lib/traceevent/Documentation/libtraceevent-endian_read.txt b/tools/lib/traceevent/Documentation/libtraceevent-endian_read.txt
new file mode 100644
index 000000000000..803819dbf51b
--- /dev/null
+++ b/tools/lib/traceevent/Documentation/libtraceevent-endian_read.txt
@@ -0,0 +1,76 @@ 
+libtraceevent(3)
+================
+
+NAME
+----
+tep_read_number - Reads a number from raw data.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <event-parse.h>*
+
+unsigned long long *tep_read_number*(struct tep_handle pass:[*]_tep_, const void pass:[*]_ptr_, int _size_);
+--
+
+DESCRIPTION
+-----------
+The _tep_read_number()_ function reads an integer from raw data, taking into
+account the endianness of the raw data and the current host. The _tep_ argument
+is the trace event parser context. The _ptr_ is a pointer to the raw data, where
+the integer is, and the _size_ is the size of the integer.
+
+RETURN VALUE
+------------
+The _tep_read_number()_ function returns the integer in the byte order of
+the current host. In case of an error, 0 is returned.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <event-parse.h>
+...
+struct tep_handle *tep = tep_alloc();
+...
+void process_record(struct tep_record *record)
+{
+	int data = tep_read_number(tep, record->data, 4);
+	/* Read the first 4 bytes of the record as integer */
+}
+...
+--
+
+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* <[e-mail]>, author of *libtraceevent*.
+*Tzvetomir Stoyanov* <[e-mail]>, author of this man page.
+--
+REPORTING BUGS
+--------------
+Report bugs to  <[e-mail]>
+
+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