diff --git a/headers/posix/unistd.h b/headers/posix/unistd.h
index 827de17441..d4ff5df379 100644
--- a/headers/posix/unistd.h
+++ b/headers/posix/unistd.h
@@ -111,6 +111,7 @@ extern int      getdtablesize(void);
 extern long		sysconf(int name);
 extern long		fpathconf(int fd, int name);
 extern long		pathconf(const char *path, int name);
+extern size_t		confstr(int name, char *buf, size_t len);
 
 /* process functions */
 extern pid_t	fork(void);
diff --git a/src/system/libroot/posix/unistd/conf.c b/src/system/libroot/posix/unistd/conf.c
index 58a63755a4..475ff4345a 100644
--- a/src/system/libroot/posix/unistd/conf.c
+++ b/src/system/libroot/posix/unistd/conf.c
@@ -100,3 +100,12 @@ pathconf(const char *path, int name)
 	return fpathconf(-1, name);
 }
 
+
+size_t 
+confstr(int name, char *buf, size_t len)
+{
+	// ToDo: find out what BeOS supports here
+	errno = EINVAL;
+	return 0;
+}
+