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$FreeBSD: releng/10.3/share/man/man9/module.9 241471 2012-10-12 01:31:02Z kevlo $
.Dd July 19, 2007 .Dt MODULE 9 .Os .Sh NAME .Nm module .Nd structure describing a kernel module .Sh DESCRIPTION Each module in the kernel is described by a .Vt module_t structure. The structure contains the name of the device, a unique ID number, a pointer to an event handler function and to an argument, which is given to the event handler, as well as some kernel internal data.
p The .Xr DECLARE_MODULE 9 macro registers the module with the system.
p When the module is loaded, the event handler function is called with the .Fa what argument set to .Dv MOD_LOAD .
p On unload it is first called with .Fa what set to .Dv MOD_QUIESCE . If the unload was not forced, a non-zero return will prevent the unload from happening.
p If the unload continues .Fa what is set to .Dv MOD_UNLOAD . If the module returns non-zero to this, the unload will not happen.
p The difference between .Dv MOD_QUIESCE and .Dv MOD_UNLOAD is that the module should fail .Dv MOD_QUIESCE if it is currently in use, whereas .Dv MOD_UNLOAD should only fail if it is impossible to unload the module, for instance because there are memory references to the module which cannot be revoked.
p When the system is shutting down, .Fa what contains the value of .Dv MOD_SHUTDOWN .
p The module should return .Er EOPNOTSUPP for unsupported and unrecognized values of .Fa what . .Sh EXAMPLES d -literal #include <sys/param.h> #include <sys/kernel.h> #include <sys/module.h> static int foo_handler(module_t mod, int /*modeventtype_t*/ what, void *arg); static moduledata_t mod_data= { "foo", foo_handler, NULL }; MODULE_VERSION(foo, 1); MODULE_DEPEND(foo, bar, 1, 3, 4); DECLARE_MODULE(foo, mod_data, SI_SUB_EXEC, SI_ORDER_ANY); .Ed .Sh SEE ALSO .Xr DECLARE_MODULE 9 , .Xr DEV_MODULE 9 , .Xr DRIVER_MODULE 9 , .Xr MODULE_DEPEND 9 , .Xr MODULE_VERSION 9 , .Xr SYSCALL_MODULE 9
p
a /usr/share/examples/kld .Sh AUTHORS This manual page was written by .An Alexander Langer Aq alex@FreeBSD.org .