summaryrefslogtreecommitdiff
path: root/absl/flags
diff options
context:
space:
mode:
Diffstat (limited to 'absl/flags')
-rw-r--r--absl/flags/declare.h6
-rw-r--r--absl/flags/flag.h2
-rw-r--r--absl/flags/flag_test.cc13
3 files changed, 19 insertions, 2 deletions
diff --git a/absl/flags/declare.h b/absl/flags/declare.h
index a791b667..d1437bb9 100644
--- a/absl/flags/declare.h
+++ b/absl/flags/declare.h
@@ -60,7 +60,11 @@ ABSL_NAMESPACE_END
// The ABSL_DECLARE_FLAG(type, name) macro expands to:
//
// extern absl::Flag<type> FLAGS_name;
-#define ABSL_DECLARE_FLAG(type, name) \
+#define ABSL_DECLARE_FLAG(type, name) ABSL_DECLARE_FLAG_INTERNAL(type, name)
+
+// Internal implementation of ABSL_DECLARE_FLAG to allow macro expansion of its
+// arguments. Clients must use ABSL_DECLARE_FLAG instead.
+#define ABSL_DECLARE_FLAG_INTERNAL(type, name) \
extern absl::Flag<type> FLAGS_##name; \
namespace absl /* block flags in namespaces */ {} \
/* second redeclaration is to allow applying attributes */ \
diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index 50106082..d2750b31 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -163,7 +163,6 @@ ABSL_NAMESPACE_END
// Note: do not construct objects of type `absl::Flag<T>` directly. Only use the
// `ABSL_FLAG()` macro for such construction.
#define ABSL_FLAG(Type, name, default_value, help) \
- extern ::absl::Flag<Type> FLAGS_##name; \
ABSL_FLAG_IMPL(Type, name, default_value, help)
// ABSL_FLAG().OnUpdate()
@@ -266,6 +265,7 @@ ABSL_NAMESPACE_END
// global name for FLAGS_no<flag_name> symbol, thus preventing the possibility
// of defining two flags with names foo and nofoo.
#define ABSL_FLAG_IMPL(Type, name, default_value, help) \
+ extern ::absl::Flag<Type> FLAGS_##name; \
namespace absl /* block flags in namespaces */ {} \
ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help) \
diff --git a/absl/flags/flag_test.cc b/absl/flags/flag_test.cc
index 6e974a5b..ced332d4 100644
--- a/absl/flags/flag_test.cc
+++ b/absl/flags/flag_test.cc
@@ -977,3 +977,16 @@ TEST_F(FlagTest, TesTypeWrappingEnum) {
value = absl::GetFlag(FLAGS_test_enum_wrapper_flag);
EXPECT_EQ(value.e, B);
}
+
+// This is a compile test to ensure macros are expanded within ABSL_FLAG and
+// ABSL_DECLARE_FLAG.
+#define FLAG_NAME_MACRO(name) prefix_ ## name
+ABSL_DECLARE_FLAG(int, FLAG_NAME_MACRO(test_macro_named_flag));
+ABSL_FLAG(int, FLAG_NAME_MACRO(test_macro_named_flag), 0,
+ "Testing macro expansion within ABSL_FLAG");
+
+TEST_F(FlagTest, MacroWithinAbslFlag) {
+ EXPECT_EQ(absl::GetFlag(FLAGS_prefix_test_macro_named_flag), 0);
+ absl::SetFlag(&FLAGS_prefix_test_macro_named_flag, 1);
+ EXPECT_EQ(absl::GetFlag(FLAGS_prefix_test_macro_named_flag), 1);
+}