tracefs_options_get_supported(3) — Linux manual page
LIBTRACEFS(3) libtracefs Manual LIBTRACEFS(3)
NAME
tracefs_options_get_supported, tracefs_option_is_supported,
tracefs_options_get_enabled, tracefs_option_is_enabled,
tracefs_option_mask_is_set, tracefs_option_id - Get and check
ftrace options.
SYNOPSIS
#include <tracefs.h>
const struct tracefs_options_mask *tracefs_options_get_supported(struct tracefs_instance *instance);
bool tracefs_option_is_supported(struct tracefs_instance *instance, enum tracefs_option_id id);
const struct tracefs_options_mask *tracefs_options_get_enabled(struct tracefs_instance *instance);
bool tracefs_option_is_enabled(struct tracefs_instance *instance, enum tracefs_option_id id);
bool tracefs_option_mask_is_set(const struct tracefs_options_mask options, enum tracefs_option_id id);
enum tracefs_option_id *tracefs_option_id(const char *name);
DESCRIPTION
This set of APIs can be used to get and check current ftrace
options. Supported ftrace options may depend on the kernel
version and the kernel configuration.
The tracefs_options_get_supported() function gets all ftrace
options supported by the system in the given instance. If
instance is NULL, supported options of the top trace instance are
returned. The set of supported options is the same in all created
trace instances, but may be different than the top trace
instance.
The *tracefs_option_is_supported()/ function checks if the option
with given id is supported by the system in the given instance.
If instance is NULL, the top trace instance is used. If an option
is supported at the top trace instance, it it may not be
supported in a created trace instance.
The tracefs_options_get_enabled() function gets all ftrace
options, currently enabled in the given instance. If instance is
NULL, enabled options of the top trace instance are returned.
The tracefs_option_is_enabled() function checks if the option
with given id is enabled in the given instance. If instance is
NULL, the top trace instance is used.
The tracefs_option_mask_is_set() function checks if the bit,
corresponding to the option with id is set in the options bitmask
returned from tracefs_option_get_enabled() and
tracefs_option_is_supported().
The tracefs_option_id() converts an option name into its
corresponding id, if it is found. This allows to find the option
id to use in the other functions if only the name is known.
RETURN VALUE
The tracefs_options_get_supported() and
tracefs_options_get_enabled() functions, on success, return a
pointer to the bitmask within the instance, or a global bitmask
for the top level, or NULL in case of an error. As the returned
bitmask is part of the instance structure (or a global variable)
and must not be freed or modified.
The tracefs_option_is_supported() and tracefs_option_is_enabled()
functions return true if the option in supported / enabled, or
false otherwise.
The tracefs_option_mask_is_set() returns true if the
corresponding option is set in the mask or false otherwise.
The tracefs_option_id() returns the corresponding id defined by
tracefs_options(3) from the given name. If the name can not be
found, then TRACEFS_OPTION_INVALID is returned.
EXAMPLE
#include <tracefs.h>
...
const struct tracefs_options_mask *options;
...
options = tracefs_options_get_supported(NULL);
if (!options) {
/* Failed to get supported options */
} else {
...
}
...
options = tracefs_options_get_enabled(NULL);
if (!options) {
/* Failed to get options, enabled in the top instance */
} else {
...
}
if (tracefs_options_mask_is_set(options, TRACEFS_OPTION_LATENCY_FORMAT)) {
...
}
...
if (tracefs_option_is_supported(NULL, TRACEFS_OPTION_LATENCY_FORMAT)) {
/* Latency format option is supprted */
}
...
if (tracefs_option_is_enabled(NULL, TRACEFS_OPTION_STACKTRACE)) {
/* Stacktrace option is enabled in the top instance */
}
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)
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) 2020 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
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