diff --git a/scsh/syscalls.c b/scsh/syscalls.c
index 153f7cb..75f636c 100644
--- a/scsh/syscalls.c
+++ b/scsh/syscalls.c
@@ -273,6 +273,19 @@ scheme_value df_setpgid(long nargs, scheme_value *args)
     return ret1;
     }
 
+scheme_value df_setsid(long nargs, scheme_value *args)
+{
+    extern pid_t setsid(void);
+    scheme_value ret1;
+    pid_t r1;
+
+    cig_check_nargs(1, nargs, "setsid");
+    r1 = setsid();
+    ret1 = errno_or_false(r1);
+    VECTOR_REF(*args,0) = ENTER_FIXNUM(r1);
+    return ret1;
+    }
+
 scheme_value df_umask(long nargs, scheme_value *args)
 {
     
diff --git a/scsh/syscalls.scm b/scsh/syscalls.scm
index a6fdf94..1c91249 100644
--- a/scsh/syscalls.scm
+++ b/scsh/syscalls.scm
@@ -210,7 +210,8 @@
 (define-foreign parent-pid (getppid) pid_t)
 
 
-;;; Process Groups   -dalbertz
+;;; Process groups and session ids
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define-foreign process-group (getpgrp) pid_t)
 (define-foreign %set-process-group/errno
@@ -220,12 +221,22 @@
 (define-simple-errno-syscall (%set-process-group pid pgrp)
   %set-process-group/errno)
 
+
 (define (set-process-group arg1 . maybe-arg2)
   (receive (pid pgrp) (if (null? maybe-arg2)
 			  (values (pid) arg1)
 			  (values arg1 (car maybe-arg2)))
 	   (%set-process-group pid pgrp)))
 
+
+(define-foreign become-session-leader/errno (setsid)
+  (multi-rep (to-scheme pid_t errno_or_false)
+	     pid_t))
+
+(define-errno-syscall (become-session-leader) become-session-leader/errno
+  sid)
+
+
 ;;; UMASK
 
 (define-foreign set-umask (umask (mode_t mask)) no-declare ; integer on SunOS
@@ -665,7 +676,6 @@
 	     integer))
 
 
-
 ;;; Signals (rather incomplete)
 ;;; ---------------------------