diff --git a/doc/chibi.scrbl b/doc/chibi.scrbl
index 4507bea5..bce8d759 100755
--- a/doc/chibi.scrbl
+++ b/doc/chibi.scrbl
@@ -783,7 +783,9 @@ Any of these may fail and return the OOM exception object.
 \item{\ccode{sexp_debug(sexp ctx, char* msg, sexp obj)} - write \var{obj} with a debug message prefix to \scheme{current-error-port}}
 \item{\ccode{sexp_read_from_string(sexp ctx, char* str, int len)} - read a single datum from \var{str}, using at most \var{len} bytes if \var{len} is non-negative}
 \item{\ccode{sexp_write_to_string(sexp ctx, sexp obj)} - return a Scheme string representation of \var{obj}}
-\item{\ccode{sexp_make_input_string_port(sexp ctx, sexp str)} - equivalent to \scheme{open-input-string}}
+\item{\ccode{sexp_open_input_string(sexp ctx, sexp str)} - equivalent to \scheme{open-input-string}}
+\item{\ccode{sexp_open_output_string(sexp ctx)} - equivalent to \scheme{open-output-string}}
+\item{\ccode{sexp_get_output_string(sexp ctx, sexp port)} - equivalent to \scheme{open-output-string}}
 ]
 
 \subsubsection{Utilities}
diff --git a/include/chibi/sexp.h b/include/chibi/sexp.h
index 7f532217..24675fa7 100755
--- a/include/chibi/sexp.h
+++ b/include/chibi/sexp.h
@@ -1383,8 +1383,8 @@ SEXP_API sexp sexp_set_port_fold_case (sexp ctx, sexp self, sexp_sint_t n, sexp
 #if SEXP_USE_OBJECT_BRACE_LITERALS
 SEXP_API sexp sexp_lookup_type_op (sexp ctx, sexp self, sexp_sint_t n, sexp name, sexp id);
 #endif
-SEXP_API sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp str);
-SEXP_API sexp sexp_make_output_string_port_op (sexp ctx, sexp self, sexp_sint_t n);
+SEXP_API sexp sexp_open_input_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp str);
+SEXP_API sexp sexp_open_output_string_op (sexp ctx, sexp self, sexp_sint_t n);
 SEXP_API sexp sexp_get_output_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp port);
 SEXP_API sexp sexp_make_exception (sexp ctx, sexp kind, sexp message, sexp irritants, sexp procedure, sexp source);
 SEXP_API sexp sexp_user_exception (sexp ctx, sexp self, const char *msg, sexp x);
@@ -1524,8 +1524,8 @@ SEXP_API sexp sexp_finalize_c_type (sexp ctx, sexp self, sexp_sint_t n, sexp obj
 #define sexp_string_concatenate(ctx, ls, s) sexp_string_concatenate_op(ctx, NULL, 2, ls, s)
 #define sexp_memq(ctx, a, b) sexp_memq_op(ctx, NULL, 2, a, b)
 #define sexp_assq(ctx, a, b) sexp_assq_op(ctx, NULL, 2, a, b)
-#define sexp_make_output_string_port(ctx) sexp_make_output_string_port_op(ctx, NULL, 0)
-#define sexp_make_input_string_port(ctx, s) sexp_make_input_string_port_op(ctx, NULL, 1, s)
+#define sexp_open_output_string(ctx) sexp_open_output_string_op(ctx, NULL, 0)
+#define sexp_open_input_string(ctx, s) sexp_open_input_string_op(ctx, NULL, 1, s)
 #define sexp_get_output_string(ctx, out) sexp_get_output_string_op(ctx, NULL, 1, out)
 #define sexp_expt(ctx, a, b) sexp_expt_op(ctx, NULL, 2, a, b)
 #define sexp_register_simple_type(ctx, a, b, c) sexp_register_simple_type_op(ctx, NULL, 3, a, b, c)
diff --git a/lib/chibi/io/port.c b/lib/chibi/io/port.c
index fbdd2d48..a1b5483b 100644
--- a/lib/chibi/io/port.c
+++ b/lib/chibi/io/port.c
@@ -195,7 +195,7 @@ static sexp sexp_make_custom_port (sexp ctx, sexp self,
   sexp_gc_preserve2(ctx, res, str);
   str = sexp_make_string(ctx, sexp_make_fixnum(SEXP_PORT_BUFFER_SIZE), SEXP_VOID);
   if (sexp_exceptionp(str)) return str;
-  res = sexp_make_input_string_port(ctx, str);
+  res = sexp_open_input_string(ctx, str);
   if (sexp_exceptionp(res)) return res;
   if (mode && mode[0] == 'w') {
     sexp_pointer_tag(res) = SEXP_OPORT;
@@ -252,14 +252,14 @@ sexp sexp_open_input_bytevector (sexp ctx, sexp self, sexp vec) {
   sexp_assert_type(ctx, sexp_bytesp, SEXP_BYTES, vec);
   sexp_gc_preserve2(ctx, str, res);
   str = sexp_bytes_to_string(ctx, vec);
-  res = sexp_make_input_string_port(ctx, str);
+  res = sexp_open_input_string(ctx, str);
   sexp_port_binaryp(res) = 1;
   sexp_gc_release2(ctx);
   return res;
 }
 
 sexp sexp_open_output_bytevector (sexp ctx, sexp self) {
-  sexp res = sexp_make_output_string_port(ctx);
+  sexp res = sexp_open_output_string(ctx);
   sexp_port_binaryp(res) = 1;
   return res;
 }
diff --git a/opcodes.c b/opcodes.c
index 3b372260..b0bf7b70 100644
--- a/opcodes.c
+++ b/opcodes.c
@@ -187,8 +187,8 @@ _FN2(_I(SEXP_OBJECT), _I(SEXP_OBJECT), SEXP_NULL, "memq", 0, sexp_memq_op),
 _FN2(_I(SEXP_OBJECT), _I(SEXP_OBJECT), SEXP_NULL, "assq", 0, sexp_assq_op),
 _FN3(_I(SEXP_SYNCLO), _I(SEXP_ENV), SEXP_NULL, _I(SEXP_OBJECT), "make-syntactic-closure", 0, sexp_make_synclo_op),
 _FN1(_I(SEXP_OBJECT), _I(SEXP_OBJECT), "strip-syntactic-closures", 0, sexp_strip_synclos),
-_FN0(_I(SEXP_OPORT), "open-output-string", 0, sexp_make_output_string_port_op),
-_FN1(_I(SEXP_IPORT), _I(SEXP_STRING), "open-input-string", 0, sexp_make_input_string_port_op),
+_FN0(_I(SEXP_OPORT), "open-output-string", 0, sexp_open_output_string_op),
+_FN1(_I(SEXP_IPORT), _I(SEXP_STRING), "open-input-string", 0, sexp_open_input_string_op),
 _FN1(_I(SEXP_STRING), _I(SEXP_OPORT), "get-output-string", 0, sexp_get_output_string_op),
 _FN2OPT(_I(SEXP_IPORT), _I(SEXP_FIXNUM), _I(SEXP_BOOLEAN), "open-input-file-descriptor", SEXP_FALSE, sexp_open_input_file_descriptor),
 _FN2OPT(_I(SEXP_OPORT), _I(SEXP_FIXNUM), _I(SEXP_BOOLEAN), "open-output-file-descriptor", SEXP_FALSE, sexp_open_output_file_descriptor),
diff --git a/sexp.c b/sexp.c
index 83db093b..ea138221 100644
--- a/sexp.c
+++ b/sexp.c
@@ -1282,7 +1282,7 @@ static off_t sstream_seek (void *vec, off_t offset, int whence) {
   return pos;
 }
 
-sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
+sexp sexp_open_input_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
   FILE *in;
   sexp res;
   sexp_gc_var1(cookie);
@@ -1301,7 +1301,7 @@ sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp st
   return res;
 }
 
-sexp sexp_make_output_string_port_op (sexp ctx, sexp self, sexp_sint_t n) {
+sexp sexp_open_output_string_op (sexp ctx, sexp self, sexp_sint_t n) {
   FILE *out;
   sexp res, size;
   sexp_gc_var1(cookie);
@@ -1335,7 +1335,7 @@ sexp sexp_get_output_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp port) {
 
 #else  /* SEXP_USE_STRING_STREAMS && ! SEXP_BSD */
 
-sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
+sexp sexp_open_input_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
   FILE *in;
   sexp res;
   sexp_assert_type(ctx, sexp_stringp, SEXP_STRING, str);
@@ -1355,7 +1355,7 @@ sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp st
   return res;
 }
 
-sexp sexp_make_output_string_port_op (sexp ctx, sexp self, sexp_sint_t n) {
+sexp sexp_open_output_string_op (sexp ctx, sexp self, sexp_sint_t n) {
   sexp res = sexp_make_output_port(ctx, NULL, SEXP_FALSE);
   sexp_port_stream(res)
     = open_memstream(&sexp_port_buf(res), &sexp_port_size(res));
@@ -1520,7 +1520,7 @@ int sexp_buffered_flush (sexp ctx, sexp p, int forcep) {
   return res;
 }
 
-sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
+sexp sexp_open_input_string_op (sexp ctx, sexp self, sexp_sint_t n, sexp str) {
   sexp res;
   sexp_assert_type(ctx, sexp_stringp, SEXP_STRING, str);
   res = sexp_make_input_port(ctx, NULL, SEXP_FALSE);
@@ -1533,7 +1533,7 @@ sexp sexp_make_input_string_port_op (sexp ctx, sexp self, sexp_sint_t n, sexp st
   return res;
 }
 
-sexp sexp_make_output_string_port_op (sexp ctx, sexp self, sexp_sint_t n) {
+sexp sexp_open_output_string_op (sexp ctx, sexp self, sexp_sint_t n) {
   sexp res = sexp_make_output_port(ctx, NULL, SEXP_FALSE);
   if (sexp_exceptionp(res)) return res;
   sexp_port_buf(res) = (char*) sexp_malloc(SEXP_PORT_BUFFER_SIZE);
@@ -1579,7 +1579,7 @@ sexp sexp_open_input_file_descriptor (sexp ctx, sexp self, sexp_sint_t n, sexp f
     return sexp_file_exception(ctx, self, "invalid file descriptor", fileno);
   sexp_gc_preserve2(ctx, res, str);
   str = sexp_make_string(ctx, sexp_make_fixnum(SEXP_PORT_BUFFER_SIZE), SEXP_VOID);
-  res = sexp_make_input_string_port(ctx, str);
+  res = sexp_open_input_string(ctx, str);
   if (!sexp_exceptionp(res)) {
     sexp_port_fd(res) = fileno;
     sexp_port_offset(res) = SEXP_PORT_BUFFER_SIZE;
@@ -3067,7 +3067,7 @@ sexp sexp_read_from_string (sexp ctx, const char *str, sexp_sint_t len) {
   sexp_gc_var2(s, in);
   sexp_gc_preserve2(ctx, s, in);
   s = sexp_c_string(ctx, str, len);
-  in = sexp_make_input_string_port(ctx, s);
+  in = sexp_open_input_string(ctx, s);
   res = sexp_read(ctx, in);
   sexp_gc_release2(ctx);
   return res;
@@ -3084,7 +3084,7 @@ sexp sexp_string_to_number_op (sexp ctx, sexp self, sexp_sint_t n, sexp str, sex
       || (sexp_string_data(str)[1]=='\0' && !sexp_isxdigit((unsigned char)(sexp_string_data(str)[0]))))
     return SEXP_FALSE;
   sexp_gc_preserve1(ctx, in);
-  in = sexp_make_input_string_port(ctx, str);
+  in = sexp_open_input_string(ctx, str);
   if (sexp_string_data(str)[0] == '+') {
     if (sexp_isdigit((unsigned char)(sexp_string_data(str)[1]))
         || sexp_string_data(str)[1] == '.' || sexp_string_data(str)[1] == '#')
@@ -3100,7 +3100,7 @@ sexp sexp_write_to_string (sexp ctx, sexp obj) {
   sexp str;
   sexp_gc_var1(out);
   sexp_gc_preserve1(ctx, out);
-  out = sexp_make_output_string_port(ctx);
+  out = sexp_open_output_string(ctx);
   str = sexp_write(ctx, obj, out);
   if (! sexp_exceptionp(str))
     str = sexp_get_output_string(ctx, out);