Man page - tracefs_binary_close(3)

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Manual

LIBTRACEFS

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
EXAMPLE
FILES
SEE ALSO
AUTHOR
REPORTING BUGS
LICENSE
RESOURCES
COPYING
NOTES

NAME

tracefs_binary_init, tracefs_binary_close, tracefs_binary_write - Open, close and write binary data in the trace buffer.

SYNOPSIS

#include <tracefs.h>

int tracefs_binary_init (struct tracefs_instance * instance );
int tracefs_binary_write (struct tracefs_instance * instance , void * data , int len );
void tracefs_binary_close (struct tracefs_instance * instance );

DESCRIPTION

Set of functions to write binary data in the trace buffer. See Documentation/trace/ftrace.rst from the Linux kernel tree for more information about writing data from user space in the trace buffer. All these APIs have instance as a first argument. If NULL is passed as instance , the top trace instance is used.

The tracefs_binary_init() function initializes the library for writing into the trace buffer of the selected instance . It is not mandatory to call this API before writing data, the tracefs_binary_write() will call it automatically, if the library is not yet initialized. But calling tracefs_binary_init() in advance will speed up the writing.

The tracefs_binary_write() function writes a binary data in the trace buffer of the selected instance . The data points to the data with length len , that is going to be written in the trace buffer.

The tracefs_binary_close() function closes the resources, used by the library for writing in the trace buffer of the selected instance.

RETURN VALUE

The tracefs_binary_init() , and tracefs_binary_write() functions return 0 if the operation is successful, or -1 in case of an error.

EXAMPLE

#include <tracefs.h>

if (tracefs_binary_init(NULL) < 0) {
/* Failed to initialize the library for writing in the trace buffer of the top trace instance */
}

unsigned int data = 0xdeadbeef;

if (tracefs_binary_write(NULL, &data, sizeof(data)) < 0) {
/* Failed to write in the trace buffer */
}

tracefs_binary_close();

FILES

tracefs.h
Header file to include in order to have access to the library APIs.
-ltracefs
Linker switch to add when building a program that uses the library.

SEE ALSO

libtracefs (3), libtraceevent (3), trace-cmd (1), Documentation/trace/ftrace.rst from the Linux kernel tree

AUTHOR

Steven Rostedt < rostedt@goodmis.org [1] >
Tzvetomir Stoyanov < tz.stoyanov@gmail.com [2] >

REPORTING BUGS

Report bugs to < linux-trace-devel@vger.kernel.org [3] >

LICENSE

libtracefs is Free Software licensed under the GNU LGPL 2.1

RESOURCES

https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/

COPYING

Copyright (C) 2021 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).

NOTES

1.

rostedt@goodmis.org

mailto:rostedt@goodmis.org

2.

tz.stoyanov@gmail.com

mailto:tz.stoyanov@gmail.com

3.

linux-trace-devel@vger.kernel.org

mailto:linux-trace-devel@vger.kernel.org