# tracefs_option_enable

## NAME



           tracefs_option_enable, tracefs_option_disable, tracefs_option_name
           - Various trace option functions.
    


## SYNOPSIS



           **#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_);
    


## DESCRIPTION



           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.
    


## EXAMPLE



               #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.
    


## 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
    


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