# tep_load_plugins

## NAME



           tep_load_plugins, tep_unload_plugins, tep_load_plugins_hook,
           tep_add_plugin_path, tep_plugin_add_option - Load / unload
           traceevent plugins.
    


## SYNOPSIS



           **#include <event-parse.h>**
    
           struct tep_plugin_list * **tep_load_plugins**(struct tep_handle *_tep_);
           void **tep_unload_plugins**(struct tep_plugin_list *_plugin_list_ , struct tep_handle *_tep_);
           void **tep_load_plugins_hook**(struct tep_handle *_tep_ , const char *_suffix_ ,
                                      void (*_load_plugin_)(struct tep_handle *tep,
                                                          const char *path,
                                                          const char *name,
                                                          void *data),
                                      void *_data_);
           int **tep_add_plugin_path**(struct tep_handle *tep, char *path,
                                     enum tep_plugin_load_priority prio);
           int **tep_plugin_add_option**(const char *_name_ , const char *_val_);
    


## DESCRIPTION



           The **tep_load_plugins()** function loads all plugins, located in the
           plugin directories. The _tep_ argument is trace event parser
           context. The plugin directories are :
    
                       - Directories, specified in _tep_ →plugins_dir with priority TEP_PLUGIN_FIRST
                       - System’s plugin directory, defined at the library compile time. It
                         depends on the library installation prefix and usually is
                         _(install_preffix)/lib/traceevent/plugins_
                       - Directory, defined by the environment variable _TRACEEVENT_PLUGIN_DIR_
                       - User’s plugin directory, located at _~/.local/lib/traceevent/plugins_
                       - Directories, specified in _tep_ →plugins_dir with priority TEP_PLUGIN_LAST
    
           Loading of plugins can be controlled by the _tep_flags_ , using the
           **tep_set_flag()** API:
    
                       _TEP_DISABLE_SYS_PLUGINS_       - do not load plugins, located in
                                                       the system’s plugin directory.
                       _TEP_DISABLE_PLUGINS_           - do not load any plugins.
    
           The **tep_set_flag()** API needs to be called before
           **tep_load_plugins()** , if loading of all plugins is not the desired
           case.
    
           The **tep_unload_plugins()** function unloads the plugins, previously
           loaded by **tep_load_plugins()**. The _tep_ argument is trace event
           parser context. The _plugin_list_ is the list of loaded plugins,
           returned by the **tep_load_plugins()** function.
    
           The **tep_load_plugins_hook()** function walks through all directories
           with plugins and calls user specified **load_plugin()** hook for each
           plugin file. Only files with given _suffix_ are considered to be
           plugins. The _data_ is a user specified context, passed to
           **load_plugin()**. Directories and the walk order are the same as in
           **tep_load_plugins()** API.
    
           The **tep_add_plugin_path()** functions adds additional directories
           with plugins in the _tep_ →plugins_dir list. It must be called before
           **tep_load_plugins()** in order for the plugins from the new
           directories to be loaded. The _tep_ argument is the trace event
           parser context. The _path_ is the full path to the new plugin
           directory. The _prio_ argument specifies the loading priority order
           for the new directory of plugins. The loading priority is
           important in case of different versions of the same plugin located
           in multiple plugin directories.The last loaded plugin wins. The
           priority can be:
    
                       _TEP_PLUGIN_FIRST_      - Load plugins from this directory first
                       _TEP_PLUGIN_LAST_       - Load plugins from this directory last
    
           Where the plugins in TEP_PLUGIN_LAST" will take precedence over
           the plugins in the other directories.
    
           The **tep_plugin_add_option()** sets options defined by a plugin. The
           _name_ is the name of the option to set to _val_. Plugins can add
           options to change its behavior and **tep_plugin_add_option()** is used
           by the application to make those modifications.
    


## RETURN VALUE



           The **tep_load_plugins()** function returns a list of successfully
           loaded plugins, or NULL in case no plugins are loaded. The
           **tep_add_plugin_path()** function returns -1 in case of an error, 0
           otherwise.
    


## EXAMPLE



               #include <event-parse.h>
               ...
               struct tep_handle *tep = tep_alloc();
               ...
               tep_add_plugin_path(tep, "~/dev_plugins", TEP_PLUGIN_LAST);
               ...
               struct tep_plugin_list *plugins = tep_load_plugins(tep);
               if (plugins == NULL) {
                       /* no plugins are loaded */
               }
               ...
               tep_unload_plugins(plugins, tep);
               ...
               void print_plugin(struct tep_handle *tep, const char *path,
                                 const char *name, void *data)
               {
                       pritnf("Found libtraceevent plugin %s/%s\n", path, name);
               }
               ...
               tep_load_plugins_hook(tep, ".so", print_plugin, NULL);
               ...
    


## FILES



               **event-parse.h**
                       Header file to include in order to have access to the library APIs.
               **-ltraceevent**
                       Linker switch to add when building a program that uses the library.
    


## LICENSE



           libtraceevent is Free Software licensed under the GNU LGPL 2.1
    


## RESOURCES



           **https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/ **
    


## 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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