diff -up netpbm-10.47.04/editor/pnmsmooth.c.pnmsmooth-segfault netpbm-10.47.04/editor/pnmsmooth.c
--- netpbm-10.47.04/editor/pnmsmooth.c.pnmsmooth-segfault	2009-10-21 13:38:57.000000000 +0200
+++ netpbm-10.47.04/editor/pnmsmooth.c	2009-03-23 07:55:01.000000000 +0100
@@ -23,12 +23,12 @@
 #include <unistd.h>
 #include <string.h>
 #include <errno.h>
+#include <sys/wait.h>
 
 #include "pm_c_util.h"
 #include "mallocvar.h"
 #include "shhopt.h"
 #include "nstring.h"
-#include "pm_system.h"
 #include "pnm.h"
 
 
@@ -176,6 +176,38 @@ writeConvolutionImage(FILE *       const
 
 
 
+static void
+runPnmconvol(const char * const inputFilespec,
+             const char * const convolutionImageFilespec) {
+
+    /* fork a Pnmconvol process */
+    pid_t rc;
+
+    rc = fork();
+    if (rc < 0)
+        pm_error("fork() failed.  errno=%d (%s)", errno, strerror(errno));
+    else if (rc == 0) {
+        /* child process executes following code */
+
+        execlp("pnmconvol",
+               "pnmconvol", convolutionImageFilespec, inputFilespec,
+               NULL);
+
+        pm_error("error executing pnmconvol command.  errno=%d (%s)",
+                 errno, strerror(errno));
+    } else {
+        /* This is the parent */
+        pid_t const childPid = rc;
+
+        int status;
+
+        /* wait for child to finish */
+        while (wait(&status) != childPid);
+    }
+}
+
+
+
 int
 main(int argc, char ** argv) {
 
@@ -200,8 +232,7 @@ main(int argc, char ** argv) {
     if (cmdline.dump) {
         /* We're done.  Convolution image is in user's file */
     } else {
-        pm_system_lp("pnmconvol", NULL, NULL, NULL, NULL,
-                     tempfileName, cmdline.inputFilespec, NULL);
+        runPnmconvol(cmdline.inputFilespec, tempfileName);
 
         unlink(tempfileName);
         strfree(tempfileName);