--- a/src/utils.h
+++ b/src/utils.h
@@ -36,74 +36,74 @@
 class octave_value_list;
 class string_vector;
 
-extern bool valid_identifier (const char *s);
-extern bool valid_identifier (const std::string& s);
+extern OCTINTERP_API bool valid_identifier (const char *s);
+extern OCTINTERP_API bool valid_identifier (const std::string& s);
 
-extern int almost_match (const std::string& std, const std::string& s,
+extern OCTINTERP_API int almost_match (const std::string& std, const std::string& s,
 			 int min_match_len = 1, int case_sens = 1);
 
-extern int
+extern OCTINTERP_API int
 keyword_almost_match (const char * const *std, int *min_len,
 		      const std::string& s, int min_toks_to_match,
 		      int max_toks);
 
-extern int empty_arg (const char *name, octave_idx_type nr, octave_idx_type nc);
+extern OCTINTERP_API int empty_arg (const char *name, octave_idx_type nr, octave_idx_type nc);
 
-extern std::string
+extern OCTINTERP_API std::string
 search_path_for_file (const std::string&, const string_vector&);
 
-extern string_vector
+extern OCTINTERP_API string_vector
 search_path_for_all_files (const std::string&, const string_vector&);
 
-extern std::string file_in_path (const std::string&, const std::string&);
-extern std::string fcn_file_in_path (const std::string&);
-extern std::string oct_file_in_path (const std::string&);
-extern std::string mex_file_in_path (const std::string&);
+extern OCTINTERP_API std::string file_in_path (const std::string&, const std::string&);
+extern OCTINTERP_API std::string fcn_file_in_path (const std::string&);
+extern OCTINTERP_API std::string oct_file_in_path (const std::string&);
+extern OCTINTERP_API std::string mex_file_in_path (const std::string&);
 
-extern std::string do_string_escapes (const std::string& s);
+extern OCTINTERP_API std::string do_string_escapes (const std::string& s);
 
-extern const char *undo_string_escape (char c);
+extern OCTINTERP_API const char *undo_string_escape (char c);
 
-extern std::string undo_string_escapes (const std::string& s);
+extern OCTINTERP_API std::string undo_string_escapes (const std::string& s);
 
-extern void
+extern OCTINTERP_API void
 check_dimensions (dim_vector& dim, const char *warnfor);
 
-extern void
+extern OCTINTERP_API void
 get_dimensions (const octave_value& a, const char *warn_for,
                 dim_vector& dim);
 
-extern void
+extern OCTINTERP_API void
 get_dimensions (const octave_value& a, const octave_value& b,
 		const char *warn_for, octave_idx_type& nr, octave_idx_type& nc);
 
-extern void
+extern OCTINTERP_API void
 get_dimensions (const octave_value& a,
 		const char *warn_for, octave_idx_type& nr, octave_idx_type& nc);
 
-extern Matrix identity_matrix (octave_idx_type nr, octave_idx_type nc);
+extern OCTINTERP_API Matrix identity_matrix (octave_idx_type nr, octave_idx_type nc);
 
-extern int
+extern OCTINTERP_API int
 octave_format (std::ostream& os, const char *fmt, ...);
 
-extern int
+extern OCTINTERP_API int
 octave_vformat (std::ostream& os, const char *fmt, va_list args);
 
-extern char *octave_vsnprintf (const char *fmt, va_list args);
+extern OCTINTERP_API char *octave_vsnprintf (const char *fmt, va_list args);
 
-extern char *octave_snprintf (const char *fmt, ...);
+extern OCTINTERP_API char *octave_snprintf (const char *fmt, ...);
 
-extern void octave_sleep (double seconds);
+extern OCTINTERP_API void octave_sleep (double seconds);
 
-extern "C" void octave_sleep (unsigned int seconds);
+extern "C" OCTINTERP_API void octave_sleep (unsigned int seconds);
 
-extern "C" void octave_usleep (unsigned int useconds);
+extern "C" OCTINTERP_API void octave_usleep (unsigned int useconds);
 
-extern "C" int octave_strcasecmp (const char *s1, const char *s2);
+extern "C" OCTINTERP_API int octave_strcasecmp (const char *s1, const char *s2);
 
-extern "C" int octave_strncasecmp (const char *s1, const char *s2, size_t n);
+extern "C" OCTINTERP_API int octave_strncasecmp (const char *s1, const char *s2, size_t n);
 
-extern "C" int octave_raw_vsnprintf (char *buf, size_t n, const char *fmt,
+extern "C" OCTINTERP_API int octave_raw_vsnprintf (char *buf, size_t n, const char *fmt,
 				     va_list args);
 
 #endif