diff --git a/configure.ac b/configure.ac
index 1b7d182..78a4c97 100644
--- a/configure.ac
+++ b/configure.ac
@@ -296,6 +296,7 @@ AC_CHECK_FUNCS([\
   getentropy \
   getexecname \
   getline \
+  open_memstream \
   pstat_getproc \
   sysconf \
 ])
diff --git a/test/fpurge.c b/test/fpurge.c
index 62d55da..784f32e 100644
--- a/test/fpurge.c
+++ b/test/fpurge.c
@@ -29,23 +29,36 @@
 #include <string.h>
 
 static int
-test_memstream(FILE *fp, size_t bufsz)
+test_memstream(void)
 {
+	int rc = 0;
+#if HAVE_OPEN_MEMSTREAM
+	FILE *fp;
+	char *buf = NULL;
+	size_t bufsz = 0;
+
+	fp = open_memstream(&buf, &bufsz);
+	if (fp == NULL)
+		return 1;
+
 	fputs("World", fp);
 	if (fpurge(fp) < 0)
-		return 1;
+		rc = 1;
 	fflush(fp);
 	if (bufsz != 0)
-		return 1;
-	return 0;
+		rc = 1;
+
+	fclose(fp);
+	free(buf);
+#endif
+
+	return rc;
 }
 
 int
 main(int argc, char *argv[])
 {
 	FILE *fp;
-	char *buf = NULL;
-	size_t bufsz = 0;
 	int rc;
 
 	if (fpurge(NULL) == 0)
@@ -54,13 +67,9 @@ main(int argc, char *argv[])
 	fp = fopen("/dev/zero", "r");
 	if (fpurge(fp) < 0)
 		return 1;
-
 	fclose(fp);
 
-	fp = open_memstream(&buf, &bufsz);
-	rc = test_memstream(fp, bufsz);
-	fclose(fp);
-	free(buf);
+	rc = test_memstream();
 
 	return rc;
 }