diff --git a/scsh/dirstuff1.c b/scsh/dirstuff1.c
index b57dbb0..0adbb02 100644
--- a/scsh/dirstuff1.c
+++ b/scsh/dirstuff1.c
@@ -11,6 +11,9 @@
 #include "libcig.h"
 #include "scsh_aux.h"
 
+/* Make sure our exports match up w/the implementation: */
+#include "dirstuff1.h"
+
 extern int errno;
 
 /* Linked list of malloc'd entries. */
@@ -33,7 +36,7 @@ void free_dirent_list(scm_dirent_t *entry)
 ** fnames is a vector of strings (filenames), null terminated.
 ** len is the length of fnames.
 */
-int open_dir(char *dirname,  char ***fnames, int *len)
+int open_dir(const char *dirname,  char ***fnames, int *len)
 {
     scm_dirent_t *dep, *entries;
     struct dirent *dirent;
@@ -91,14 +94,15 @@ int open_dir(char *dirname,  char ***fnames, int *len)
 
 static int compare_fname(const void *aptr, const void *bptr)
 {
-    char *a= *(char**)aptr, *b = *(char**)bptr;
+    char const *a = * (char const * *) aptr;
+    char const *b = * (char const * *) bptr;
     if( DOTFILE(a) )
 	return DOTFILE(b) ? strcmp(a+1,b+1) : -1;
     return DOTFILE(b) ? 1 : strcmp(a,b);
 }
 
 
-void scm_sort_filevec(char **dirvec, int nelts)
+void scm_sort_filevec(const char **dirvec, int nelts)
 {
     qsort((char *) dirvec, nelts, sizeof(char*), compare_fname);
     }
@@ -119,7 +123,8 @@ void scm_sort_filevec(char **dirvec, int nelts)
 
 static int comp1(const void *aptr, const void* bptr)
 {
-    char *a = *(char**)aptr, *b = *(char**)bptr;
+    char const *a = *(char const **)aptr;
+    char const *b = *(char const **)bptr;
 
     if(streq(a,b)) return 0;
 
diff --git a/scsh/dirstuff1.h b/scsh/dirstuff1.h
new file mode 100644
index 0000000..c27f91b
--- /dev/null
+++ b/scsh/dirstuff1.h
@@ -0,0 +1,4 @@
+/* Exports from dirstuff1.c. */
+
+int open_dir(const char *dirname, char ***fnames, int *len);
+void scm_sort_filevec(const char **dirvec, int nelts);
diff --git a/scsh/fdports1.c b/scsh/fdports1.c
index 1b84298..9b73a82 100644
--- a/scsh/fdports1.c
+++ b/scsh/fdports1.c
@@ -29,6 +29,9 @@
 #define NUM_FDPORTS 256
 #include "fdports.h"
 
+/* Make sure our exports match up w/the implementation: */
+#include "fdports1.h"
+
 extern int errno;
 
 /* Maps fd's to FILE*'s. */
@@ -62,7 +65,7 @@ scheme_value maybe_fdes2port(int fd)
 
 #if 0
 /* Bogus old code. We now compute the mode string from the actual fd. */
-static char *mode2string(int mode)
+static char const *mode2string(int mode)
 {
     if( mode == 0 ) return "r";
     else if( mode == 1 ) return "w";
@@ -71,7 +74,7 @@ static char *mode2string(int mode)
     }
 #endif
 
-static char *fdes_modestr(int fd)
+static char const *fdes_modestr(int fd)
 {
     int flags = fcntl(fd,F_GETFL);
 
@@ -141,7 +144,7 @@ int flush_all_ports(void)
 /*  return fflush(NULL) ? errno : 0;  THE REAL SOLUTION.*/
     }
 
-int seek_fdport(scheme_value data, int offset, int whence, int *newpos)
+int seek_fdport(scheme_value data, off_t offset, int whence, int *newpos)
 {
     FILE *f = fstar_cache[EXTRACT_FIXNUM(*PortData_Fd(data))];
     *PortData_Peek(data) = SCHFALSE; /* Flush buffered data. */
@@ -185,6 +188,15 @@ int close_fdport(scheme_value port_data)
     else return EBADF; /* Already closed. */
     }
 
+
+static int cloexec_fdport(scheme_value port_data)
+{
+    int fd = EXTRACT_FIXNUM(*PortData_Fd(port_data));
+
+    return fcntl(fd, F_SETFD, FD_CLOEXEC) ? errno : 0;
+    }
+
+
 /*  Set all the unrevealed ports to close-on-exec.
     This is called right before an exec, which is sleazy;
     we should have the port-revealing machinery set and reset
@@ -202,18 +214,11 @@ void cloexec_unrevealed(void)
 	}
     }
 
-int cloexec_fdport(scheme_value port_data)
-{
-    int fd = EXTRACT_FIXNUM(*PortData_Fd(port_data));
-
-    return fcntl(fd, F_SETFD, FD_CLOEXEC) ? errno : 0;
-    }
-
 
 int install_port(int fd, scheme_value port)
 {
     FILE *stream;
-    char *modestr;
+    const char *modestr;
 
     if( fd < 0 || fd >= NUM_FDPORTS ) return -1;
     if( fdports[fd] != SCHFALSE ) return -2;
@@ -225,20 +230,19 @@ int install_port(int fd, scheme_value port)
     if( fstar_cache[fd] ) return 0; /* A hack mainly for stdio. */
 
     fstar_cache[fd] = stream = fdopen(fd, modestr);
-    return stream == NULL ? errno : 0;
+    return stream ? 0 : errno;
     }
 
 
 FILE *fdes2fstar(int fd)
 {
-    char *modestr;
-
     if( fstar_cache[fd] ) return fstar_cache[fd];
-    if( !(modestr=fdes_modestr(fd)) ) return NULL;
-    return fdopen(fd, modestr);
+    else {
+	const char *modestr = fdes_modestr(fd);
+	return modestr ? fdopen(fd, modestr) : NULL;
+	}
     }
 
-
 /* fd_from's FILE* structure is changed to be fd_to's FILE* structure.
 ** So buffered data isn't lost. Return 0 on failure.
 ** Rather non-portable.
@@ -392,8 +396,9 @@ int write_fdport_substring(scheme_value buf, int start, int end, scheme_value da
 **   termination.
 */
 
-int read_delim(const char *delims, char *buf, int gobble, scheme_value port, 
-	       int start, int end, int *nread)
+scheme_value read_delim(const char *delims, char *buf, int gobble,
+			scheme_value port, int start, int end,
+			int *nread)
 {
 
     scheme_value data  = *Port_PortData(port);
diff --git a/scsh/fdports1.h b/scsh/fdports1.h
new file mode 100644
index 0000000..5bc22a3
--- /dev/null
+++ b/scsh/fdports1.h
@@ -0,0 +1,41 @@
+/* Exports from fdports1.c. */
+
+void init_fdports(void);
+
+scheme_value maybe_fdes2port(int fd);
+
+scheme_value fdport_getchar(scheme_value data);
+
+int fdport_putchar(scheme_value data, char c);
+
+scheme_value fdport_char_readyp(scheme_value data);
+
+int flush_fdport(scheme_value data);
+
+int flush_all_ports(void);
+
+int seek_fdport(scheme_value data, off_t offset, int whence, int *newpos);
+
+int tell_fdport( scheme_value data, int *newpos );
+
+int set_fdbuf( scheme_value data, int policy, int bufsize );
+
+int close_fdport(scheme_value port_data);
+
+void cloexec_unrevealed(void);
+
+int install_port(int fd, scheme_value port);
+
+FILE *fdes2fstar(int fd);
+
+int move_fdport(int fd, scheme_value port, int new_revealed);
+
+void post_gc_fdports(void);
+
+int read_fdport_substring(scheme_value buf, int start, int end, scheme_value data);
+
+int write_fdport_substring(scheme_value buf, int start, int end, scheme_value data);
+
+scheme_value read_delim(const char *delims, char *buf, int gobble,
+			scheme_value port, int start, int end,
+			int *nread);
diff --git a/scsh/flock.c b/scsh/flock.c
index 7c8cb26..780760f 100644
--- a/scsh/flock.c
+++ b/scsh/flock.c
@@ -12,6 +12,9 @@
 
 extern int errno;
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "flock1.h"
+
 #define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)
 
 scheme_value df_set_lock(long nargs, scheme_value *args)
diff --git a/scsh/flock.scm b/scsh/flock.scm
index b9383a0..474e4ee 100644
--- a/scsh/flock.scm
+++ b/scsh/flock.scm
@@ -15,6 +15,9 @@
   ""
   "extern int errno;"
   ""
+  "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+  "#include \"flock1.h\""
+  ""
   "#define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)"
   "" "")
 
diff --git a/scsh/flock1.c b/scsh/flock1.c
index 2a29f1d..a1958dc 100644
--- a/scsh/flock1.c
+++ b/scsh/flock1.c
@@ -9,6 +9,9 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+/* Make sure our exports match up w/the implementation: */
+#include "flock1.h"
+
 int set_lock(int fd, int cmd, int type, int whence, int start, int len)
 {
     struct flock lock;
diff --git a/scsh/flock1.h b/scsh/flock1.h
new file mode 100644
index 0000000..0dd26a0
--- /dev/null
+++ b/scsh/flock1.h
@@ -0,0 +1,5 @@
+/* Exports from flock1.c. */
+
+int set_lock(int fd, int cmd, int type, int whence, int start, int len);
+int get_lock(int fd, int cmd, int type, int whence, int start, int len,
+	     int *rtype, int *rwhence, int *rstart, int *rlen, int *rpid);
diff --git a/scsh/network.c b/scsh/network.c
index ac2e055..1046381 100644
--- a/scsh/network.c
+++ b/scsh/network.c
@@ -9,6 +9,8 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "network1.h"
 
 extern int errno;
 extern int h_errno;
@@ -289,14 +291,14 @@ scheme_value df_scheme_net_address2net_info(long nargs, scheme_value *args)
 
 scheme_value df_scheme_net_name2net_info(long nargs, scheme_value *args)
 {
-    extern int scheme_net_name2net_info(const char *, const char *, char **, char** *);
+    extern int scheme_net_name2net_info(const char *, scheme_value , char **, char** *);
     scheme_value ret1;
     int r1;
     char *r2;
     char** r3;
 
     cig_check_nargs(3, nargs, "scheme_net_name2net_info");
-    r1 = scheme_net_name2net_info(cig_string_body(args[2]), cig_string_body(args[1]), &r2, &r3);
+    r1 = scheme_net_name2net_info(cig_string_body(args[2]), args[1], &r2, &r3);
     ret1 = False_on_zero(r1);
     {AlienVal(CAR(VECTOR_REF(*args,0))) = (long) r2; CDR(VECTOR_REF(*args,0)) = strlen_or_false(r2);}
     AlienVal(VECTOR_REF(*args,1)) = (long) r3;
@@ -381,22 +383,22 @@ scheme_value df_scheme_proto_name2proto_info(long nargs, scheme_value *args)
 
 scheme_value df_veclen(long nargs, scheme_value *args)
 {
-    extern scheme_value veclen(long* );
+    extern scheme_value veclen(const long * );
     scheme_value ret1;
     scheme_value r1;
 
     cig_check_nargs(1, nargs, "veclen");
-    r1 = veclen((long* )AlienVal(args[0]));
+    r1 = veclen((const long * )AlienVal(args[0]));
     ret1 = r1;
     return ret1;
     }
 
 scheme_value df_set_longvec_carriers(long nargs, scheme_value *args)
 {
-    extern void set_longvec_carriers(scheme_value , char** );
+    extern void set_longvec_carriers(scheme_value , long const * const * );
 
     cig_check_nargs(2, nargs, "set_longvec_carriers");
-    set_longvec_carriers(args[1], (char** )AlienVal(args[0]));
+    set_longvec_carriers(args[1], (long const * const * )AlienVal(args[0]));
     return SCHFALSE;
     }
 
diff --git a/scsh/network.scm b/scsh/network.scm
index dd0fc07..ed95ff5 100644
--- a/scsh/network.scm
+++ b/scsh/network.scm
@@ -8,6 +8,8 @@
  "#include <sys/types.h>"
  "#include <sys/socket.h>"
  ""
+ "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+ "#include \"network1.h\""
  ""
  "extern int errno;"
  "extern int h_errno;"
@@ -781,9 +783,7 @@
 			     (string->integer net))))))
 		  
 (define-foreign %net-address->network-info
-  (scheme_net_address2net_info 
-   (string-desc name)
-   (string-desc net))
+  (scheme_net_address2net_info (string-desc name) (string-desc net))
   (to-scheme integer "False_on_zero")
   static-string	; net name
   (C char**))   ; alias list
@@ -801,9 +801,7 @@
 			      (string->integer net))))))
 		  
 (define-foreign %net-name->network-info
-  (scheme_net_name2net_info 
-   (string name)
-   (string net))
+  (scheme_net_name2net_info (string name) (string-desc net))
   (to-scheme integer "False_on_zero")
   static-string	 ; net name
   (C char**))    ; alias list
@@ -839,9 +837,7 @@
 				       protocol))))))
 		  
 (define-foreign %service-port->service-info
-  (scheme_serv_port2serv_info 
-   (integer name)
-   (string  proto))
+  (scheme_serv_port2serv_info (integer name) (string  proto))
   (to-scheme integer "False_on_zero")
   static-string	 ; service name
   (C char**)     ; alias list
@@ -864,9 +860,7 @@
 			      protocol)))))
 		  
 (define-foreign %service-name->service-info
-  (scheme_serv_name2serv_info 
-   (string name)
-   (string proto))
+  (scheme_serv_name2serv_info (string name) (string proto))
   (to-scheme integer "False_on_zero")
   static-string	 ; service name
   (C char**)     ; alias list
@@ -954,12 +948,13 @@
 
 ;; also from cig/libcig.scm
 (define-foreign %c-veclen-or-false
-  (veclen ((C long*) c-vec))		; redefining can we open cig-aux?
+  (veclen ((C "const long * ~a") c-vec)); redefining can we open cig-aux?
   desc) ; integer or #f if arg is NULL.
 
 ;; also from cig/libcig.scm
 (define-foreign %set-long-vector-carriers!
-  (set_longvec_carriers (vector-desc svec) ((C char**) cvec))
+  (set_longvec_carriers (vector-desc svec)
+			((C "long const * const * ~a") cvec))
   ignore)
 
 ;; also from cig/libcig.scm
diff --git a/scsh/network1.c b/scsh/network1.c
index 6f09bf0..02cb5f5 100644
--- a/scsh/network1.c
+++ b/scsh/network1.c
@@ -17,6 +17,9 @@
 #include <string.h>
 #include <stdio.h>
 
+/* Make sure our exports match up w/the implementation: */
+#include "network1.h"
+
 extern int h_errno;
 
 /* to extract a 4 byte long value from a scheme string */
@@ -396,7 +399,7 @@ int scheme_host_address2host_info(scheme_value scheme_name,
   return(0);
 }
 
-int scheme_host_name2host_info(char*   scheme_name,
+int scheme_host_name2host_info(const char* scheme_name,
 			       char**  hostname,
 			       char*** aliases,
 			       char*** addresses)
@@ -448,8 +451,8 @@ int scheme_net_address2net_info(scheme_value scheme_name,
   return(0);
 }
 
-int scheme_net_name2net_info(char*   scheme_name,
-			     char*   scheme_net,
+int scheme_net_name2net_info(const char*   scheme_name,
+			     scheme_value  scheme_net,
 			     char**  netname,
 			     char*** aliases)
 {
@@ -464,19 +467,21 @@ int scheme_net_name2net_info(char*   scheme_name,
   
   *netname=net->n_name;
   *aliases=net->n_aliases;
-  SET_LONG(scheme_net,0,net->n_net);
+  SET_LONG(scheme_net,0,net->n_net);	/* ??? -Olin */
   return(0);
 }
 
 /*-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-*/
 /* Routines for looking up services                                        */
 /*-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-*/
-int scheme_serv_port2serv_info(u_short   in_port,
-			       char*     in_proto,
-			       char**    out_servname,
-			       char***   out_aliases,
-			       int*      out_port,
-			       char**    out_protocol)
+
+/* in_port should be declared u_short, but cig doesn't know about them. */
+int scheme_serv_port2serv_info(int in_port,
+			       const char* in_proto,
+			       char**      out_servname,
+			       char***     out_aliases,
+			       int*        out_port,
+			       char**      out_protocol)
 {
   struct servent *serv;
 
@@ -498,8 +503,8 @@ int scheme_serv_port2serv_info(u_short   in_port,
   return(0);
 }
 
-int scheme_serv_name2serv_info(char*    in_name,
-			       char*    in_proto,
+int scheme_serv_name2serv_info(const char*    in_name,
+			       const char*    in_proto,
 			       char**   out_servname,
 			       char***  out_aliases,
 			       int*     out_port,
@@ -549,7 +554,7 @@ int scheme_proto_num2proto_info(int     in_proto,
   return(0);
 }
 
-int scheme_proto_name2proto_info(char*   in_name,
+int scheme_proto_name2proto_info(const char* in_name,
 				 char**  out_protoname,
 				 char*** out_aliases,
 				 int*    out_protocol)
@@ -595,9 +600,9 @@ void set_longvec_carriers(scheme_value svec, long const * const * cvec)
 **  The terminating null is not counted. Returns #f on NULL.
 */
 
-scheme_value veclen(long *vec)
+scheme_value veclen(const long *vec)
 {
-  long *vptr = vec;
+  const long *vptr = vec;
   if( !vptr ) return SCHFALSE;
   while( *vptr ) vptr++;
   return ENTER_FIXNUM(vptr - vec);
diff --git a/scsh/network1.h b/scsh/network1.h
new file mode 100644
index 0000000..88dcfca
--- /dev/null
+++ b/scsh/network1.h
@@ -0,0 +1,99 @@
+/* Exports from network1.c. */
+
+int scheme_bind(int sockfd, int family, scheme_value scheme_name);
+
+int scheme_connect(int sockfd, int family, scheme_value scheme_name);
+
+int scheme_accept(int sockfd, int family, scheme_value scheme_name);
+
+int scheme_peer_name(int sockfd, int family, scheme_value scheme_name);
+
+int scheme_socket_name(int sockfd, int family, scheme_value scheme_name);
+
+int scheme_socket_pair(int type, int *s1, int *s2);
+
+int recv_substring(int s, int flags, scheme_value buf, 
+		   int start, int end, scheme_value scheme_name);
+
+int send_substring(int s, int flags, scheme_value buf, int start, int end,
+		   int family, scheme_value scheme_name);
+
+int scheme_getsockopt (int s, int level, int optname);
+
+int scheme_getsockopt_linger (int s,
+			      int level,
+			      int optname,
+			      int *out_time);
+
+int scheme_getsockopt_timeout (int s,
+			       int level,
+			       int optname,
+			       int *out_usec);
+
+int scheme_setsockopt (int s,
+		       int level,
+		       int optname,
+		       int optval);
+
+int scheme_setsockopt_linger (int s,
+			      int level,
+			      int optname,
+			      int onoff,
+			      int linger);
+
+int scheme_setsockopt_timeout (int s,
+			       int level,
+			       int optname,
+			       int sec,
+			       int usec);
+
+int scheme_host_address2host_info(scheme_value scheme_name,
+				  char** hostname,
+				  char*** aliases,
+				  char*** addresses);
+
+int scheme_host_name2host_info(const char* scheme_name,
+			       char**  hostname,
+			       char*** aliases,
+			       char*** addresses);
+
+int scheme_net_address2net_info(scheme_value scheme_name,
+				scheme_value scheme_net,
+				char** netname,
+				char*** aliases);
+
+int scheme_net_name2net_info(const char* scheme_name,
+			     scheme_value scheme_net,
+			     char**  netname,
+			     char*** aliases);
+
+
+/* in_port should be declared u_short, but cig doesn't know about them. */
+
+int scheme_serv_port2serv_info(int in_port,
+			       const char* in_proto,
+			       char**	   out_servname,
+			       char***     out_aliases,
+			       int*        out_port,
+			       char**      out_protocol);
+
+int scheme_serv_name2serv_info(const char* in_name,
+			       const char* in_proto,
+			       char**   out_servname,
+			       char***  out_aliases,
+			       int*     out_port,
+			       char**   out_protocol);
+
+int scheme_proto_num2proto_info(int     in_proto,
+				char**  out_protoname,
+				char*** out_aliases,
+				int*    out_protocol);
+
+int scheme_proto_name2proto_info(const char*   in_name,
+				 char**  out_protoname,
+				 char*** out_aliases,
+				 int*    out_protocol);
+
+void set_longvec_carriers(scheme_value svec, long const * const * cvec);
+
+scheme_value veclen(const long *vec);
diff --git a/scsh/putenv.c b/scsh/putenv.c
index f1e5acf..d1044a4 100644
--- a/scsh/putenv.c
+++ b/scsh/putenv.c
@@ -25,10 +25,11 @@ extern char **environ;
 
 /* Internal utility.
 ** Copy the entire env to a new block, and add the new definition.
+** Drop the old block on the floor; can't free() it.
 ** Return 0 if win
 **        non-zero if the malloc fails.
 */
-static int append_envvar(const char *str, int old_envsize)
+static int append_envvar(char *str, int old_envsize)
 {
     char **envp, **nenvp;
     char **newenv = Malloc(char*, 1+old_envsize);
@@ -56,12 +57,14 @@ static int append_envvar(const char *str, int old_envsize)
 ** another putenv() call), so altering str changes the environment.
 **
 ** Malloc is used to allocate new environ vectors. 
+** In neither replacement strategy are we able to free() the unused
+** storage; it is simply dropped on the floor.
 ** Putenv returns
 **   0 if it wins;
 **   non-zero if str doesn't contain an '=' char or if the malloc fails.
 */
 
-int putenv(const char *str)
+int putenv(char *str)
 {
     char **envp = environ;
     char *equalsign = strchr(str, '=');
diff --git a/scsh/rdelim.c b/scsh/rdelim.c
index f8b9f77..5fef311 100644
--- a/scsh/rdelim.c
+++ b/scsh/rdelim.c
@@ -6,6 +6,11 @@
 #include <stdlib.h> /* For malloc. */
 #include "libcig.h"
 
+#include <sys/types.h>
+
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "fdports1.h"
+
 scheme_value df_read_delim(long nargs, scheme_value *args)
 {
     extern scheme_value read_delim(const char *, char *, int , scheme_value , int , int , int *);
diff --git a/scsh/rdelim.scm b/scsh/rdelim.scm
index 524e31e..8a73fc7 100644
--- a/scsh/rdelim.scm
+++ b/scsh/rdelim.scm
@@ -195,6 +195,13 @@
 			  (lp (+ i 1))))))))))
 
 
+(foreign-source
+  "#include <sys/types.h>"
+  ""
+  "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+  "#include \"fdports1.h\""
+  "" "")
+
 (define-foreign %read-delimited-fdport!/errno (read_delim (string delims)
 							  (var-string buf)
 							  (bool gobble?)
diff --git a/scsh/re.c b/scsh/re.c
index 82f0645..6bc0661 100644
--- a/scsh/re.c
+++ b/scsh/re.c
@@ -6,6 +6,9 @@
 #include <stdlib.h> /* For malloc. */
 #include "libcig.h"
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "re1.h"
+
 scheme_value df_reg_match(long nargs, scheme_value *args)
 {
     extern char *reg_match(const char *, const char *, int , scheme_value , scheme_value , int *);
@@ -21,3 +24,18 @@ scheme_value df_reg_match(long nargs, scheme_value *args)
     return ret1;
     }
 
+scheme_value df_filter_stringvec(long nargs, scheme_value *args)
+{
+    extern char *filter_stringvec(const char *, char const ** , int *);
+    scheme_value ret1;
+    char *r1;
+    int r2;
+
+    cig_check_nargs(3, nargs, "filter_stringvec");
+    r1 = filter_stringvec(cig_string_body(args[2]), (char const ** )AlienVal(args[1]), &r2);
+    ret1 = VECTOR_REF(*args,0);
+    {AlienVal(CAR(ret1)) = (long) r1; CDR(ret1) = strlen_or_false(r1);}
+    VECTOR_REF(*args,1) = ENTER_FIXNUM(r2);
+    return ret1;
+    }
+
diff --git a/scsh/re.scm b/scsh/re.scm
index de932fd..e4004f7 100644
--- a/scsh/re.scm
+++ b/scsh/re.scm
@@ -1,6 +1,12 @@
 ;;; Regular expression matching for scsh
 ;;; Copyright (c) 1994 by Olin Shivers.
 
+(foreign-source
+  "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+  "#include \"re1.h\""
+  "" ""
+  )
+
 (define-record regexp-match
   string
   start	; 10 elt vec
@@ -65,3 +71,12 @@
 					     start-vec end-vec)
     (if (not (equal? err "")) (error err %regexp-match)
 	match?)))
+
+
+;;; I do this one in C, I'm not sure why:
+;;; Used by MATCH-FILES.
+
+(define-foreign %filter-C-strings!
+  (filter_stringvec (string regexp) ((C "char const ** ~a") cvec))
+  static-string	; error message -- #f if no error.
+  integer)	; number of files that pass the filter.
diff --git a/scsh/re1.h b/scsh/re1.h
new file mode 100644
index 0000000..7a1762d
--- /dev/null
+++ b/scsh/re1.h
@@ -0,0 +1,6 @@
+char *reg_match(const char *re, const char *string, int start,
+		scheme_value start_vec, scheme_value end_vec,
+		int *hit);
+
+char *filter_stringvec(const char *re, char const **stringvec,
+		       int *nummatch);
diff --git a/scsh/scsh-package.scm b/scsh/scsh-package.scm
index 595d53f..474ada9 100644
--- a/scsh/scsh-package.scm
+++ b/scsh/scsh-package.scm
@@ -48,7 +48,8 @@
   (open defenum-package scheme)
   (files (machine bufpol)))
 
-(define-structure scsh-regexp-package scsh-regexp-interface
+(define-structures ((scsh-regexp-package scsh-regexp-interface)
+		    (scsh-regexp-internals (export %filter-C-strings!)))
   (open	defrec-package
 	scsh-utilities
 	define-foreign-syntax
@@ -169,6 +170,7 @@
 	weak
 
 	scsh-regexp-package
+	scsh-regexp-internals
 	char-set-package
 	scsh-version
 	tty-flags
diff --git a/scsh/select.c b/scsh/select.c
index 17843ec..38ba754 100644
--- a/scsh/select.c
+++ b/scsh/select.c
@@ -6,6 +6,9 @@
 #include <stdlib.h> /* For malloc. */
 #include "libcig.h"
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "select1.h"
+
 scheme_value df_scm_select(long nargs, scheme_value *args)
 {
     extern scheme_value scm_select(scheme_value , scheme_value , scheme_value , scheme_value , int *, int *, int *);
diff --git a/scsh/select.scm b/scsh/select.scm
index 8b6f8ca..b4b1c88 100644
--- a/scsh/select.scm
+++ b/scsh/select.scm
@@ -1,6 +1,11 @@
 ;;; select(2) syscall for scsh. -*- Scheme -*-
 ;;; Copyright (c) 1995 by Olin Shivers.
 
+(foreign-source
+  "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+  "#include \"select1.h\""
+  "" "")
+
 ;;; TIMEOUT is 0 for immediate, >0 for timeout, #f for infinite; 
 ;;;     default is #f.
 ;;; The sets are vectors of file descriptors & fd ports.
diff --git a/scsh/select1.c b/scsh/select1.c
index e4c85ab..0cdeb42 100644
--- a/scsh/select1.c
+++ b/scsh/select1.c
@@ -2,12 +2,6 @@
 ** Copyright (c) 1995 by Olin Shivers.
 */
 
-/* To do:
-** - Documentation.
-** - Check Posix timeval defn.
-** - What is proper include for error vals?
-*/
-
 #include "sysdep.h"
 
 #include <sys/types.h>
@@ -19,8 +13,12 @@
 #include <errno.h>
 #include <stdio.h>
 
-#include "fdports.h"	/* Accessors for Scheme I/O port internals. */
 #include "cstuff.h"
+#include "fdports.h"	/* Accessors for Scheme I/O port internals. */
+#include "fdports1.h"	/* Import fdes2fstar(). */
+
+/* Make sure our exports match up w/the implementation: */
+#include "select1.h"
 
 /* the traditional sleazy max non-function. */
 #define max(a,b) (((a) > (b)) ? (a) : (b))
@@ -33,7 +31,7 @@ static int copyback_fdvec(scheme_value portvec, fd_set *fdset);
 
 /* RVEC, WVEC, and EVEC are Scheme vectors of integer file descriptors
 ** and I/O ports. NSECS is an integer timeout value, or #f for infinite wait.
-** Do the select() call. Move every element of we hit on to the front of
+** Do the select() call. Move every element we hit on to the front of
 ** its vector. The number of hits are returned in R_NUMRDY, W_NUMRDY, and
 ** E_NUMRDY. The principle return value is #f if we win, and a fixnum errno
 ** value if we error out.
@@ -193,4 +191,3 @@ static void or2_fdset(fd_set *x, fd_set *y, int max_elt)
     for(i=max_elt+1; --i >= 0;)
 	if( FD_ISSET(i,y) ) FD_SET(i,x);
     }
-
diff --git a/scsh/select1.h b/scsh/select1.h
new file mode 100644
index 0000000..43602ad
--- /dev/null
+++ b/scsh/select1.h
@@ -0,0 +1,5 @@
+/* Exports from select1.c. */
+
+scheme_value scm_select(scheme_value rvec, scheme_value wvec,
+			scheme_value evec, scheme_value nsecs,
+			int *r_numrdy, int *w_numrdy, int *e_numrdy);
diff --git a/scsh/syscalls.c b/scsh/syscalls.c
index 89df30f..153f7cb 100644
--- a/scsh/syscalls.c
+++ b/scsh/syscalls.c
@@ -16,6 +16,13 @@
 #include <pwd.h>
 #include <unistd.h>
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "dirstuff1.h"
+#include "fdports1.h"
+#include "select1.h"
+#include "syscalls1.h"
+#include "userinfo1.h"
+
 extern int errno;
 
 #define errno_on_zero_or_false(x) ((x) ? SCHFALSE : ENTER_FIXNUM(errno))
@@ -829,28 +836,13 @@ scheme_value df_open_dir(long nargs, scheme_value *args)
 
 scheme_value df_scm_sort_filevec(long nargs, scheme_value *args)
 {
-    extern void scm_sort_filevec(char** , int );
+    extern void scm_sort_filevec(const char** , int );
 
     cig_check_nargs(2, nargs, "scm_sort_filevec");
-    scm_sort_filevec((char** )AlienVal(args[1]), EXTRACT_FIXNUM(args[0]));
+    scm_sort_filevec((const char** )AlienVal(args[1]), EXTRACT_FIXNUM(args[0]));
     return SCHFALSE;
     }
 
-scheme_value df_filter_stringvec(long nargs, scheme_value *args)
-{
-    extern char *filter_stringvec(const char *, char** , int *);
-    scheme_value ret1;
-    char *r1;
-    int r2;
-
-    cig_check_nargs(3, nargs, "filter_stringvec");
-    r1 = filter_stringvec(cig_string_body(args[2]), (char** )AlienVal(args[1]), &r2);
-    ret1 = VECTOR_REF(*args,0);
-    {AlienVal(CAR(ret1)) = (long) r1; CDR(ret1) = strlen_or_false(r1);}
-    VECTOR_REF(*args,1) = ENTER_FIXNUM(r2);
-    return ret1;
-    }
-
 scheme_value df_scm_envvec(long nargs, scheme_value *args)
 {
     extern char** scm_envvec(int *);
diff --git a/scsh/syscalls.scm b/scsh/syscalls.scm
index 2105d93..a6fdf94 100644
--- a/scsh/syscalls.scm
+++ b/scsh/syscalls.scm
@@ -16,6 +16,13 @@
   "#include <pwd.h>"
   "#include <unistd.h>"
   ""
+  "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+  "#include \"dirstuff1.h\""
+  "#include \"fdports1.h\""
+  "#include \"select1.h\""
+  "#include \"syscalls1.h\""
+  "#include \"userinfo1.h\""
+  ""
   "extern int errno;"
   ""
   "#define errno_on_zero_or_false(x) ((x) ? SCHFALSE : ENTER_FIXNUM(errno))"
@@ -233,6 +240,7 @@
 ;;; PROCESS TIMES
 
 ;;; OOPS: The POSIX times() has a mildly useful ret value we are throwing away.
+;;; OOPS: The ret values should be clock_t, not int, but cig can't handle it.
 
 (define-foreign process-times/errno (process_times)
   (to-scheme integer errno_or_false)
@@ -814,7 +822,7 @@
 ;;; Sorts them in place by the Unix filename order: ., .., dotfiles, others.
 
 (define-foreign %sort-file-vector
-  (scm_sort_filevec ((C char**) cvec)
+  (scm_sort_filevec ((C "const char** ~a") cvec)
 		    (integer    veclen))
   ignore)
 
@@ -831,13 +839,6 @@
 	    (filter (lambda (f) (not (char=? (string-ref f 0) #\.)))
 		    files))))))
 
-;;; I do this one in C, I'm not sure why:
-
-(define-foreign %filter-C-strings!
-  (filter_stringvec (string regexp) ((C char**) cvec))
-  static-string	; error message -- ""  if no error.
-  integer)	; number of files that pass the filter.
-
 (define (match-files regexp . maybe-dir)
   (let ((dir (optional-arg maybe-dir ".")))
     (check-arg string? dir match-files)
@@ -845,7 +846,7 @@
 	     (%open-dir (ensure-file-name-is-nondirectory dir))
       (if err (errno-error err match-files regexp dir))
       (receive (err numfiles) (%filter-C-strings! regexp cvec)
-	(if (not (equal? err "")) (error err match-files))
+	(if err (error err match-files))
 	(%sort-file-vector cvec numfiles)
 	(let ((files (C-string-vec->Scheme&free cvec numfiles)))
 	  (vector->list files))))))
diff --git a/scsh/syscalls1.c b/scsh/syscalls1.c
index 7a3123f..945862c 100644
--- a/scsh/syscalls1.c
+++ b/scsh/syscalls1.c
@@ -23,6 +23,9 @@
 
 #include "cstuff.h"
 
+/* Make sure our exports match up w/the implementation: */
+#include "syscalls1.h"
+
 extern int errno;
 extern char **environ;
 
@@ -54,7 +57,7 @@ scheme_value wait_pid(int pid, int flags, int *result_pid, int *status)
 ** on the Scheme side.
 */
 
-int scheme_exec(char *prog, scheme_value argv, scheme_value env)
+int scheme_exec(const char *prog, scheme_value argv, scheme_value env)
 {
   int i, j, e;
   int argc = VECTOR_LENGTH(argv);
@@ -118,13 +121,12 @@ int scheme_pipe(int *r, int *w)
 
 static char linkpath[MAXPATHLEN+1]; /*  Maybe unaligned. Not reentrant. */
 
-char *scm_readlink(char *path)
+char const *scm_readlink(const char *path)
 {
   int retval = readlink(path, linkpath, MAXPATHLEN);
 
-  return (retval == -1)
-    ?  NULL
-      :  ( linkpath[retval] = '\0', linkpath );
+  return (char const *)
+      (retval == -1) ? NULL : ( linkpath[retval] = '\0', linkpath );
 }
 
 
@@ -149,7 +151,7 @@ int scm_utime_now(char const *path) {return utime(path, 0);}
 */
 
 /* Simple-minded POSIX version. */
-int scheme_cwd(char **dirp)
+int scheme_cwd(const char **dirp)
 {
   char *buf;
   int size = 100;
@@ -166,7 +168,7 @@ int scheme_cwd(char **dirp)
       buf = nbuf;
     }
 
-  *dirp = buf;			/* win */
+  *dirp = (const char*) buf;		/* win */
   return 0;
 
  lose:
@@ -181,13 +183,13 @@ int scheme_cwd(char **dirp)
 /* Faster SUNOS version. */
 /* We have to use malloc, because the stub is going to free the string. */
 
-int scheme_cwd(char **dirp)
+int scheme_cwd(const char **dirp)
 {
   char *buf = Malloc(char,MAXPATHLEN); 
   int e;
 
   if( buf && getwd(buf) ) {
-    *dirp = buf;
+    *dirp = (const char*) buf;
     return 0;
   }
 
@@ -204,8 +206,11 @@ int scheme_cwd(char **dirp)
 *******************************************************************************
 */
 
-long process_times(clock_t *utime, clock_t *stime,
-		   clock_t *cutime, clock_t *cstime)
+/* Sleazing on the types here -- the ret values should be clock_t, not int,
+** but cig can't handle it.
+*/
+
+int process_times(int *utime, int *stime, int *cutime, int *cstime)
 {
     struct tms tms;
     clock_t t = times(&tms);
@@ -217,7 +222,7 @@ long process_times(clock_t *utime, clock_t *stime,
     return t;
     }
 
-long cpu_clock_ticks_per_sec() 
+int cpu_clock_ticks_per_sec() 
 {
 #ifdef _SC_CLK_TCK
   static long clock_tick = 0;
@@ -257,9 +262,7 @@ int read_fdes_substring(scheme_value buf, int start, int end, int fd)
 
 #define Min(a,b) (((a) < (b)) ? (a) : (b))	/* Not a function. */
 
-/* Warning -- This fun is not very portable, since we use _iobuf internals.
-**
-** Also, note the clearerr() call. This is so a ^D on a tty input stream
+/* Note the clearerr() call. This is so a ^D on a tty input stream
 ** doesn't shut the stream down forever. SunOS doesn't handle this according
 ** to POSIX spec, so we have to explicitly hack this case.
 */
@@ -365,7 +368,7 @@ static int really_stat(int retval, struct stat *s, scheme_value vec)
   return 0;
 }
 
-int scheme_stat(char *path, scheme_value vec, int chase_p)
+int scheme_stat(const char *path, scheme_value vec, int chase_p)
 {
   struct stat s;
   return really_stat(chase_p ? stat(path, &s) : lstat(path, &s), &s, vec);
@@ -465,7 +468,7 @@ int install_env(scheme_value vec)
 
 
 /* Delete the env var. */
-void delete_env(char *var)
+void delete_env(const char *var)
 {
   int varlen = strlen(var);
   char **ptr = environ-1;
@@ -484,17 +487,17 @@ void delete_env(char *var)
 */
 static char hostname[MAXHOSTNAMELEN+1]; 
 
-scheme_value scm_gethostname(void)
+char *scm_gethostname(void)
 {
-  /* different OS's declare differently, so punt the prototype. */
-  int gethostname(); 
-  gethostname(hostname, MAXHOSTNAMELEN);
-  return (scheme_value) hostname;
-}
+    /* different OS's declare differently, so punt the prototype. */
+    int gethostname(); 
+    gethostname(hostname, MAXHOSTNAMELEN);
+    return hostname;
+    }
 
 #include <errno.h>
 
-const char *errno_msg(int i)
+char *errno_msg(int i)
 {
   /* temp hack until we figure out what to do about losing sys_errlist's */
 #ifdef HAVE_CONST_SYS_ERRLIST
@@ -502,10 +505,9 @@ const char *errno_msg(int i)
 #endif
     extern char *sys_errlist[]; 
   extern int sys_nerr;
-  return ( i < 0 || i > sys_nerr )
-    ? (char*) NULL		/* i.e., #f */
-      : sys_errlist[i];
-}
+  return ( i < 0 || i > sys_nerr ) ? NULL		/* i.e., #f */
+      				   : (char*) sys_errlist[i];
+  }
 
 /* Some of fcntl()
 ******************
diff --git a/scsh/syscalls1.h b/scsh/syscalls1.h
new file mode 100644
index 0000000..e23221c
--- /dev/null
+++ b/scsh/syscalls1.h
@@ -0,0 +1,55 @@
+/* Exports from syscalls1.c. */
+
+scheme_value wait_pid(int pid, int flags, int *result_pid, int *status);
+
+int scheme_exec(const char *prog, scheme_value argv, scheme_value env);
+
+int scheme_pipe(int *r, int *w);
+
+char const *scm_readlink(const char *path);
+
+int scm_utime(char const *path, int ac_hi, int ac_lo, int mod_hi, int mod_lo);
+
+int scm_utime_now(char const *path);
+
+int scheme_cwd(const char **dirp);
+
+int process_times(int *utime, int *stime, int *cutime, int *cstime);
+
+int cpu_clock_ticks_per_sec();
+
+scheme_value read_fdes_char(int fd);
+
+int write_fdes_char(char c, int fd);
+
+int read_fdes_substring(scheme_value buf, int start, int end, int fd);
+
+int read_stream_substring(scheme_value buf, int start, int end, FILE *f);
+
+int write_fdes_substring(scheme_value buf, int start, int end, int fd);
+
+int write_stream_substring(scheme_value buf, int start, int end, FILE *f);
+
+int scheme_stat(const char *path, scheme_value vec, int chase_p);
+
+int scheme_fstat(int fd, scheme_value vec);
+
+int num_supp_groups(void);
+
+int get_groups(scheme_value gvec);
+
+int put_env(const char *s);
+
+char** scm_envvec(int *len);
+
+int install_env(scheme_value vec);
+
+void delete_env(const char *var);
+
+char *scm_gethostname(void);
+
+char *errno_msg(int i);
+
+int fcntl_read(int fd, int command);
+
+int fcntl_write(int fd, int command, int value);
diff --git a/scsh/tty.c b/scsh/tty.c
index 324b4f9..bab93c9 100644
--- a/scsh/tty.c
+++ b/scsh/tty.c
@@ -8,12 +8,15 @@
 
 #include <termios.h>
 
+/* Make sure foreign-function stubs interface to the C funs correctly: */
+#include "tty1.h"
+
 extern int errno;
 
 #define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)
 scheme_value df_scheme_tcgetattr(long nargs, scheme_value *args)
 {
-    extern int scheme_tcgetattr(int , const char *, int *, int *, int *, int *, int *, int *, int *, int *, int *, int *);
+    extern int scheme_tcgetattr(int , char *, int *, int *, int *, int *, int *, int *, int *, int *, int *, int *);
     scheme_value ret1;
     int r1;
     int r2;
diff --git a/scsh/tty.scm b/scsh/tty.scm
index 03a600b..218c1fd 100644
--- a/scsh/tty.scm
+++ b/scsh/tty.scm
@@ -16,6 +16,9 @@
 (foreign-source
  "#include <termios.h>"
  ""
+ "/* Make sure foreign-function stubs interface to the C funs correctly: */"
+ "#include \"tty1.h\""
+ ""
  "extern int errno;"
  ""
  "#define errno_or_false(x) (((x) == -1) ? ENTER_FIXNUM(errno) : SCHFALSE)"
@@ -107,7 +110,7 @@
 
 (define-foreign %tty-info/errno
   (scheme_tcgetattr (integer fdes)
-		    (string  control-chars))
+		    (var-string control-chars))
   (to-scheme integer errno_or_false)
   integer integer
   integer integer
diff --git a/scsh/tty1.c b/scsh/tty1.c
index d27abb4..10b857a 100644
--- a/scsh/tty1.c
+++ b/scsh/tty1.c
@@ -1,5 +1,7 @@
 /* To do:
  * - Replace explicit 8/24 splits with macros.
+ * - We need to pass the control-chars vecs in as Scheme
+ *   strings, and test the length before doing the memcpy.
  */
 
 /* 
@@ -12,7 +14,9 @@
 #include <termios.h>
 #include <string.h>
 
-int scheme_tcgetattr(int fd,	     char control_chars[NCCS],
+#include "tty1.h"	/* Make sure the .h interface agrees with the code. */
+
+int scheme_tcgetattr(int fd,	     char *control_chars,
 		     int *iflag_hi8, int *iflag_lo24,
 		     int *oflag_hi8, int *oflag_lo24,
 		     int *cflag_hi8, int *cflag_lo24,
@@ -37,7 +41,7 @@ int scheme_tcgetattr(int fd,	     char control_chars[NCCS],
 
 
 int scheme_tcsetattr(int fd,	    int option,
-		     char *control_chars,
+		     const char *control_chars,
 		     int iflag_hi8, int iflag_lo24,
 		     int oflag_hi8, int oflag_lo24,
 		     int cflag_hi8, int cflag_lo24,
diff --git a/scsh/tty1.h b/scsh/tty1.h
new file mode 100644
index 0000000..3ad12ba
--- /dev/null
+++ b/scsh/tty1.h
@@ -0,0 +1,17 @@
+/* Exports from tty1.c. */
+
+int scheme_tcgetattr(int fd,	     char *control_chars,
+		     int *iflag_hi8, int *iflag_lo24,
+		     int *oflag_hi8, int *oflag_lo24,
+		     int *cflag_hi8, int *cflag_lo24,
+		     int *lflag_hi8, int *lflag_lo24,
+		     int *ispeed,    int *ospeed);
+
+int scheme_tcsetattr(int fd,	    int option,
+		     const char *control_chars,
+		     int iflag_hi8, int iflag_lo24,
+		     int oflag_hi8, int oflag_lo24,
+		     int cflag_hi8, int cflag_lo24,
+		     int lflag_hi8, int lflag_lo24,
+		     int ispeed,    int ospeed,
+		     int min,	    int time);
diff --git a/scsh/userinfo1.h b/scsh/userinfo1.h
new file mode 100644
index 0000000..eee60f9
--- /dev/null
+++ b/scsh/userinfo1.h
@@ -0,0 +1,14 @@
+/* Exports from userinfo1.c. */
+
+char *my_username(void);
+
+int user_info_uid(uid_t uid, 
+		  char **name, gid_t *gid, char **dir, char **shell);
+
+int user_info_name(const char *name,
+		   uid_t *uid, gid_t *gid, char **dir, char **shell);
+
+int group_info_gid (int gid,  char **name, char ***members, int *nmembers);
+
+int group_info_name (const char *name,
+		     int *gid, char ***members, int *nmembers);