SYSCALL_MODULE(9)      FreeBSD Kernel Developer's Manual     SYSCALL_MODULE(9)

NAME

     SYSCALL_MODULE - syscall kernel module declaration macro

SYNOPSIS

     #include <sys/param.h>
     #include <sys/kernel.h>
     #include <sys/proc.h>
     #include <sys/module.h>
     #include <sys/sysent.h>

     SYSCALL_MODULE(name, int *offset, struct sysent *new_sysent,
         modeventhand_t evh, void *arg);

DESCRIPTION

     The SYSCALL_MODULE() macro declares a new syscall.  SYSCALL_MODULE()
     expands into a kernel module declaration with name `sys/name'.

     The rest of the arguments expected by this macro are:

     offset      A pointer to an int which saves the offset in struct sysent
                 where the syscall is allocated.  If the location pointed to
                 by offset holds a non 0 number it will be used if possible.
                 If it holds 0 then one will be assigned.

     new_sysent  is a pointer to a structure that specifies the function
                 implementing the syscall and the number of arguments this
                 function needs (see <sys/sysent.h>).

     evh         A pointer to the kernel module event handler function with
                 the argument arg.  Please refer to module(9) for more
                 information.

     arg         The argument passed to the callback functions of the evh
                 event handler when it is called.

     The syscall number assigned to the module can be retrieved using the
     modstat(2) and modfind(2) system calls.  The MACRO
     SYSCALL_MODULE_HELPER() includes SYSCALL_MODULE() and much of its
     boilerplate code.

EXAMPLES

     A minimal example for a syscall module can be found in
     /usr/share/examples/kld/syscall/module/syscall.c.

SEE ALSO

     module(9)

     /usr/share/examples/kld/syscall/module/syscall.c

AUTHORS

     This manual page was written by Alexander Langer <alex@FreeBSD.org>.

FreeBSD 15.1-STABLE-HBSD         June 15, 2023               SYSCALL_MODULE(9)