tracefs_option_enable(3)

Usage

#include <tracefs.h>
int tracefs_option_enable(struct tracefs_instance *instance, enum tracefs_option_id id);
int tracefs_option_disable(struct tracefs_instance *instance, enum tracefs_option_id id);
const char *tracefs_option_name(enum tracefs_option_id id);

Overview

This set of APIs can be used to enable and disable ftrace options and to get the name of an option.

The tracefs_option_enable() function enables the option with id in the given instance. If instance is NULL, the option is enabled in the top trace instance.

The tracefs_option_disable() function disables the option with id in the given instance. If instance is NULL, the option is disabled in the top trace instance.

The tracefs_option_name() function returns a string, representing the option with id. The string must not be freed.

Return value

The tracefs_option_enable() and tracefs_option_disable() functions return 0 if the state of the option is set successfully, or -1 in case of an error.

The tracefs_option_name() function returns string with option name, or "unknown" in case of an error. The returned string must not be freed.

Examples

#include <tracefs.h>
...
if (tracefs_option_enable(NULL, TRACEFS_OPTION_ANNOTATE)) {
        /* Failed to enable annotate option in top trace instance */
}
...
if (tracefs_option_disable(NULL, TRACEFS_OPTION_CONTEXT_INFO)) {
        /* Failed to disable context info option in top trace instance */
}
...
char *name = tracefs_option_name(TRACEFS_OPTION_FUNC_STACKTRACE);
if (strcmp(name, "unknown")) {
        /* Cannot get the name of the option */
}

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.