tracefs_binary_init(3) — Linux manual page
LIBTRACEFS(3) libtracefs Manual LIBTRACEFS(3)
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
COLOPHON
This page is part of the libtracefs (Linux kernel trace file
system library) project. Information about the project can be
found at ⟨https://www.trace-cmd.org/⟩. If you have a bug report
for this manual page, see ⟨https://www.trace-cmd.org/⟩. This
page was obtained from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-17.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org