shared: add compat macro for G_PID_FORMAT

Having G_PID_FORMAT macro is useful, but it's only available in
recent glib versions. Add a compat implementation and a test that
our assumptions hold.

2 files changed, 37 insertions, 0 deletions

diff --git a/shared/nm-glib-aux/nm-glib.h b/shared/nm-glib-aux/nm-glib.h
index 9b5f1627bc..98b778f995 100644
--- a/shared/nm-glib-aux/nm-glib.h
+++ b/shared/nm-glib-aux/nm-glib.h
@@ -556,6 +556,17 @@ _nm_g_value_unset (GValue *value)
 #define g_value_unset _nm_g_value_unset
 #endif
 
+/* G_PID_FORMAT was added only in 2.53.5. Define it ourself.
+ *
+ * If this was about "pid_t", we would check SIZEOF_PID_T, and set
+ * PRIi32/PRIi16, like systemd does. But it's actually about
+ * GPid, which glib typedefs as an "int".
+ *
+ * There is a test_gpid() that check that GPid is really a typedef
+ * for int. */
+#undef G_PID_FORMAT
+#define G_PID_FORMAT "i"
+
 /*****************************************************************************/
 
 #endif  /* __NM_GLIB_H__ */
diff --git a/shared/nm-utils/tests/test-shared-general.c b/shared/nm-utils/tests/test-shared-general.c
index 51459cb235..032b79420c 100644
--- a/shared/nm-utils/tests/test-shared-general.c
+++ b/shared/nm-utils/tests/test-shared-general.c
@@ -16,6 +16,31 @@
 /*****************************************************************************/
 
 static void
+test_gpid (void)
+{
+	const int *int_ptr;
+	GPid pid = 42;
+
+	/* We redefine G_PID_FORMAT, because it's only available since glib 2.53.5.
+	 *
+	 * Also, this is the format for GPid, which for glib is always a typedef
+	 * for "int". Add a check for that here.
+	 *
+	 * G_PID_FORMAT is not about pid_t, which might be a smaller int, and which we would
+	 * check with SIZEOF_PID_T. */
+	G_STATIC_ASSERT (sizeof (GPid) == sizeof (int));
+
+	g_assert_cmpstr (""G_PID_FORMAT, ==, "i");
+
+	/* check that it's really "int". We will get a compiler warning, if that's not
+	 * the case. */
+	int_ptr = &pid;
+	g_assert_cmpint (*int_ptr, ==, 42);
+}
+
+/*****************************************************************************/
+
+static void
 test_monotonic_timestamp (void)
 {
 	g_assert (nm_utils_get_monotonic_timestamp_s () > 0);
@@ -502,6 +527,7 @@ int main (int argc, char **argv)
 {
 	nmtst_init (&argc, &argv, TRUE);
 
+	g_test_add_func ("/general/test_gpid", test_gpid);
 	g_test_add_func ("/general/test_monotonic_timestamp", test_monotonic_timestamp);
 	g_test_add_func ("/general/test_nmhash", test_nmhash);
 	g_test_add_func ("/general/test_nm_make_strv", test_make_strv);