diff --git a/include/stdbool.h b/include/stdbool.h
index 59cce7a961..4175a0f9ad 100644
--- a/include/stdbool.h
+++ b/include/stdbool.h
@@ -2,12 +2,12 @@
 #define _STDBOOL_H
 
 #ifndef __cplusplus
-typedef _Bool bool;
+#define bool _Bool
 #define true 1
 #define false 0
 #else /* __cplusplus */
-typedef bool _Bool;
 #if __cplusplus < 201103L
+#define bool bool
 #define false false
 #define true true
 #endif /*__cplusplus < 201103L*/
@@ -15,5 +15,4 @@ typedef bool _Bool;
 
 #define __bool_true_false_are_defined 1
 
-
 #endif /* _STDBOOL_H */
diff --git a/tests/stdlib/ptsname.c b/tests/stdlib/ptsname.c
index 82d2687d84..d7489401a7 100644
--- a/tests/stdlib/ptsname.c
+++ b/tests/stdlib/ptsname.c
@@ -16,12 +16,14 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#define _XOPEN_SOURCE 600
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <limits.h>
 
 #define DEV_TTY		"/dev/tty"
 #define PTSNAME_EINVAL	"./ptsname-einval"
@@ -29,21 +31,20 @@
 int do_single_test(int fd, char * buf, size_t buflen, int expected_err) {
 
     int ret = ptsname_r(fd, buf, buflen);
-    int err = errno;
 
     if (expected_err == 0) {
         if (ret != 0) {
             printf("ptsname_r: expected: return = 0\n");
-            printf("           got: return = %d, errno = %d (%s)\n",
-                ret, err, strerror(err));
+            printf("           got: return = %d (%s)\n",
+                ret, strerror(ret));
             return 1;
         }
     } else {
-        if (ret == 0 || errno != expected_err) {
-            printf("ptsname_r: expected: return = %d, errno = %d (%s)\n",
-                -1, expected_err, strerror(expected_err));
-            printf("           got: return = %d, errno = %d (%s)\n",
-                ret, err, strerror(err));
+        if (ret == 0 || ret != expected_err) {
+            printf("ptsname_r: expected: return = %d (%s)\n",
+                expected_err, strerror(expected_err));
+            printf("           got: return = %d (%s)\n",
+                ret, strerror(ret));
             return 1;
         }
     }
@@ -52,18 +53,26 @@ int do_single_test(int fd, char * buf, size_t buflen, int expected_err) {
 }
 
 int main(void) {
-    char buf[512] = {0};
+    char buf[TTY_NAME_MAX] = {0};
     int result = 0;
     errno = 0;
     /* Tests with a real PTS master.  */
     int fd = posix_openpt(O_RDWR);
-    if (fd != -1) {
-        result |= do_single_test(fd, buf, sizeof(buf), 0);
-        result |= do_single_test(fd, buf, 1, ERANGE);
-        close(fd);
-    } else
+    if (fd == -1) {
         printf("posix_openpt (O_RDWR) failed\nerrno %d (%s)\n",
             errno, strerror(errno));
+    }
+    errno = 0;
+    if (grantpt(fd) == -1) {
+        printf("grantpt(%d) failed\nerrno %d (%s)\n", fd, errno, strerror(errno));
+    }
+    errno = 0;
+    if (unlockpt(fd) == -1) {
+        printf("unlockpt(%d) failed\nerrno %d (%s)\n", fd, errno, strerror(errno));
+    }
+    result |= do_single_test(fd, buf, sizeof(buf), 0);
+    result |= do_single_test(fd, buf, 1, ERANGE);
+    close(fd);
 
     // TODO: open(DEV_TTY, O_RDONLY) gives error on CI 
     // /* Test with a terminal device which is not a PTS master.  */
@@ -77,13 +86,18 @@ int main(void) {
 
     /* Test with a file.  */
     fd = open(PTSNAME_EINVAL, O_RDWR | O_CREAT, 0600);
-    if (fd != -1) {
-        result |= do_single_test(fd, buf, sizeof(buf), ENOTTY);
-        close(fd);
-        unlink(PTSNAME_EINVAL);
-    } else
+    grantpt(fd); // grantpt() is a no-op on Linux and Redox but is needed for POSIX compliance.
+    errno = 0;
+    if (unlockpt(fd) != -1 && errno != EINVAL) {
+        printf("unlockpt(%d) did not return an expected errno\ngot errno %d (%s)\n", fd, errno, strerror(errno));
+    }
+    if (fd == -1) {
         printf("open (\"%s\", O_RDWR | OCREAT) failed\nerrno %d (%s)\n",
             PTSNAME_EINVAL, errno, strerror(errno));
+    }
+    result |= do_single_test(fd, buf, sizeof(buf), ENOTTY);
+    close(fd);
+    unlink(PTSNAME_EINVAL);
 
     return result;
-}
\ No newline at end of file
+}