v7 man page for _init

_fini(9E)							Driver Entry Points							 _fini(9E)

NAME

       _fini, _info, _init - loadable module configuration entry points

SYNOPSIS

       #include <sys/modctl.h>

       int _fini(void);

       int _info(struct modinfo *modinfop);

       int _init(void);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI). These entry points are required. You must write them.

PARAMETERS

   _info()
       modinfop        A pointer to an opaque modinfo structure.

DESCRIPTION

       _init()	initializes  a	loadable module. It is called before any other routine in a loadable module. _init() returns the value returned by
       mod_install(9F). The module may optionally perform some other work before the mod_install(9F) call is performed. If  the  module  has  done
       some  setup  before  the  mod_install(9F)  function  is called, then it should be prepared to undo that setup if mod_install(9F) returns an
       error.

       _info() returns information about a loadable module. _info() returns the value returned by mod_info(9F).

       _fini() prepares a loadable module for unloading. It is called when the system wants to unload a module. If the module determines  that	it
       can  be	unloaded,  then  _fini() returns the value returned by mod_remove(9F). Upon successful return from _fini() no other routine in the
       module will be called before _init() is called.

RETURN VALUES

       _init() should return the appropriate error number if there is an error, otherwise it should return the return value from mod_install(9F).

       _info() should return the return value from mod_info(9F)

       _fini() should return the return value from mod_remove(9F). _fini() is permitted to return EBUSY prior to  calling  mod_remove(9F)  if  the
       driver  should  not be unloaded. Driver global resources, such as mutexes and calls to ddi_soft_state_fini(9F), should only be destroyed in
       _fini() after mod_remove() returns successfully.

EXAMPLES

       Example 1: Initializing and Freeing a Mutex

       The following example demonstrates how to initialize and free a mutex(9F).

       #include <sys/modctl.h>
       #include <sys/ddi.h>
       #include <sys/sunddi.h>
       static struct dev_ops  drv_ops;
       /*
	* Module linkage information for the kernel.
	*/
       static struct modldrv modldrv = {
	    &mod_driverops,	/* Type of module.  This one is a driver */
	   "Sample Driver",
	   &drv_ops	  /* driver ops */
       };

       static struct modlinkage modlinkage = {
	       MODREV_1,
	       &modldrv,
	       NULL
       };

       /*
	* Global driver mutex
	*/
       static kmutex_t	 xx_global_mutex;

       int
       _init(void)
       {
	       int     i;

	       /*
		 * Initialize global mutex before mod_install'ing driver.
		 * If mod_install() fails, must clean up mutex initialization
		 */
	       mutex_init(&xx_global_mutex, NULL,
		       MUTEX_DRIVER, (void *)NULL);

	       if ((i = mod_install(&modlinkage)) != 0) {
		       mutex_destroy(&xx_global_mutex);
	       }

	       return (i);
       }

       int
       _info(struct modinfo *modinfop)
       {
	       return (mod_info(&modlinkage, modinfop));
       }

       int
       _fini(void)
       {
	       int	 i;

	       /*
		 * If mod_remove() is successful, we destroy our global mutex
		 */
	       if ((i = mod_remove(&modlinkage)) == 0) {
			mutex_destroy(&xx_global_mutex);
	       }
	       return (i);
       }

SEE ALSO

       add_drv(1M), mod_info(9F), mod_install(9F), mod_remove(9F), mutex(9F), modldrv(9S), modlinkage(9S), modlstrmod(9S)

       Writing Device Drivers

WARNINGS

       Do not change the structures referred to by the modlinkage structure after the call to mod_install(), as the  system  may  copy	or  change
       them.

NOTES

       Even  though the identifiers _fini(), _info(), and _init() appear to be declared as globals, their scope is restricted by the kernel to the
       module that they are defined in.

BUGS

       On some implementations _info() may be called before _init().

SunOS 5.10							    22 Jan 2002 							 _fini(9E)