diff --git a/lib/libutil/pidfile.3 b/lib/libutil/pidfile.3
--- a/lib/libutil/pidfile.3
+++ b/lib/libutil/pidfile.3
@@ -22,14 +22,16 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd May 10, 2020
+.Dd August 2, 2025
 .Dt PIDFILE 3
 .Os
 .Sh NAME
 .Nm pidfile_open ,
 .Nm pidfile_write ,
 .Nm pidfile_close ,
-.Nm pidfile_remove
+.Nm pidfile_remove ,
+.Nm pidfile_fileno ,
+.Nm pidfile_signal
 .Nd "library for PID files handling"
 .Sh LIBRARY
 .Lb libutil
@@ -45,6 +47,8 @@
 .Fn pidfile_remove "struct pidfh *pfh"
 .Ft int
 .Fn pidfile_fileno "struct pidfh *pfh"
+.Ft int
+.Fn pidfile_signal "const char *path" "int sig" "pid_t *pidptr"
 .Sh DESCRIPTION
 The
 .Nm pidfile
@@ -101,6 +105,26 @@
 The
 .Fn pidfile_fileno
 function returns the file descriptor for the open pidfile.
+.Pp
+The
+.Fn pidfile_signal
+function looks for the pidfile specified by
+.Va path ,
+and if it exists and is locked, sends the signal specified by
+.Va sig
+to the PID it contains.
+If
+.Va pidptr
+is not
+.Dv NULL ,
+the PID that was found in the pidfile is stored in the location it
+points to.
+Note that calling
+.Fn pidfile_signal
+with
+.Va sig
+set to zero is an effective way to verify the existence of a pidfile
+and of the process that owns it.
 .Sh RETURN VALUES
 The
 .Fn pidfile_open
@@ -125,6 +149,20 @@
 if a NULL
 .Vt pidfh
 is specified, or if the pidfile is no longer open.
+.Pp
+The
+.Fn pidfile_signal
+function returns 0 if it successfully signaled a process, and an
+appropriate
+.Va errno
+value otherwise.
+Note that
+.Fn pidfile_signal
+will return
+.Dv ENOENT ,
+if the pidfile exists but is not locked, and that it may also return
+.Dv ESRCH
+if called just as the process is shutting down.
 .Sh EXAMPLES
 The following example shows in which order these functions should be used.
 Note that it is safe to pass
@@ -282,6 +320,7 @@
 .El
 .Sh SEE ALSO
 .Xr open 2 ,
+.Xr kill 2 ,
 .Xr daemon 3 ,
 .Xr flopen 3
 .Sh HISTORY