ictlyh · November 30, 2016 13:42 · Nov 30, 2016
diff --git a/test-gflag.cc b/test-gflag.cc
@@ -0,0 +1,111 @@
+/*
+ * Demo of gflags
+ * Build: g++ test-gflags.cc -o test-gfalgs -lgflags
+ * // ERROR: illegal value '-1' specified for uint64 flag 'u64'
+ * ./test-gflags.out --b=false --i32=-1 --i64=1 --u64=-1 --d=10.01 -s="string value"
+ * // ERROR: failed validation of new value '11' for flag 'i32'
+ * ./test-gflags.out --b=false --i32=11 --i64=1 --u64=1 --d=10.01 -s="string value"
+ * ./test-gflags.out --b=false --i32=1 --i64=1 --u64=1 --d=10.01 extraa extrab extrac
+ *
+ * Refer to gflags.h for more detail help message of structs and function.
+ */
+
+#include <iostream>
+#include <gflags/gflags.h>
+#include <string>
+#include <vector>
+
+// move these declare statements to header file. Other source files
+// which included the header could use these flags too.
+DECLARE_bool(b);
+DECLARE_int32(i32);
+DECLARE_int64(i64);
+DECLARE_uint64(u64);
+DECLARE_double(d);
+DECLARE_string(s);
+
+DEFINE_bool(b, true, "bool value");
+DEFINE_int32(i32, 10, "int32 value");
+DEFINE_int64(i64, 10, "int64 value");
+DEFINE_uint64(u64,10, "uint64 value");
+DEFINE_double(d, 10.0, "double value");
+DEFINE_string(s, "english,french,german",
+		"comma-separated list of languages to offer in the 'lang' menu");
+
+static bool ValidateInt(const char* flagname, int value)
+{
+	if (value < 10)
+		return true;
+	return false;
+}
+
+int main(int argc, char* argv[])
+{
+	for(int i = 0; i < argc; i++)
+	{
+		std::cout << "argv[" << i << "] = " << argv[i] << std::endl;
+	}
+
+	// Demo of google::RegisterFlagValidator()
+	if (!google::RegisterFlagValidator(&FLAGS_i32, &ValidateInt))
+	{
+		std::cout << "RegisterFlagValidator fail" << std::endl;
+	}
+
+	// Demo of google::ParseCommandLineFlags()
+	// calling google::ParseCommandLineFlags(&argc, &argv, true), argvs will be reserved.
+	google::ParseCommandLineFlags(&argc, &argv, true);
+
+	// Demo of using flags and their value
+	std::cout << "FLAGS_b = " << FLAGS_b <<std::endl;
+	std::cout << "FLAGS_i32 = " << FLAGS_i32 << std::endl;
+	std::cout << "FLAGS_i64 = " << FLAGS_i64 << std::endl;
+	std::cout << "FLAGS_u64 = " << FLAGS_u64 << std::endl;
+	std::cout << "FLAGS_d = " << FLAGS_d << std::endl;
+	std::cout << "FLAGS_s = " << FLAGS_s << std::endl;
+
+	// output reserved argvs
+	for(int i = 0; i < argc; i++)
+	{
+		std::cout << "argv[" << i << "] = " << argv[i] << std::endl;
+	}
+
+	google::CommandLineFlagInfo info;
+	std::string buf;
+	// Demo of google::GetCommandLineOption()
+	google::GetCommandLineOption("s", &buf);
+
+	// Demo of google::GetCommandLineFlagInfo()
+	if (google::GetCommandLineFlagInfo("s", &info) && info.is_default)
+	{
+		std::cout << "s is not set, using default value " << info.default_value << std::endl;
+	}
+	else
+	{
+		std::cout << "s is set to " << buf << std::endl;
+	}
+
+	// Demo of google::SetCommandLineOption()
+	google::SetCommandLineOption("s", "new string value");
+	google::GetCommandLineOption("s", &buf);
+	if (google::GetCommandLineFlagInfo("s", &info) && info.is_default)
+	{
+		std::cout << "s is not set, using default value " << info.default_value << std::endl;
+	}
+	else
+	{
+		std::cout << "s is set to " << buf << std::endl;
+	}
+
+	std::cout << "Show all flags" << std::endl;
+	std::vector<google::CommandLineFlagInfo> bufs;
+	// Demo of google::GetAllFlags()
+	google::GetAllFlags(&bufs);
+	for(std::vector<google::CommandLineFlagInfo>::iterator ite = bufs.begin();
+			ite != bufs.end(); ite++)
+	{
+		std::cout << ite->name << "=" << ite->current_value << ", default: "
+			<< ite->default_value << std::endl;
+	}
+	return 0;
+}