有時候，總想驗證一些奇怪的想法，乾脆就寫下來，以備後查。

想法：多次呼叫WSAStartup會發生什麼？

void TestCase_WSAStartupAndCleanup()
{
	WORD versionRequested1_1, versionRequested2_2;
	WSADATA wsaData1_1, wsaData2_2;
	int err;

	versionRequested1_1 = MAKEWORD(1, 1);
	versionRequested2_2 = MAKEWORD(2, 2);

	err = WSAStartup(versionRequested1_1, &wsaData1_1 );
	if ( err != 0 ) {
		printf_s("wsa startup failed. [%u] \n", WSAGetLastError());
		return;
	}
	printf_s("wsa startup success. [%u.%u] \n", LOBYTE(wsaData1_1.wVersion), HIBYTE(wsaData1_1.wVersion));

	// 模擬中間其他函式又初始化網路的情況
	{
		err = WSAStartup(versionRequested2_2, &wsaData2_2 );
		if ( err != 0 ) {
			printf_s("wsa startup failed. [%u] \n", WSAGetLastError());
			return;
		}
		printf_s("wsa startup success. [%u.%u] \n", LOBYTE(wsaData2_2.wVersion), HIBYTE(wsaData2_2.wVersion));

		// do something ...

		if ( LOBYTE( wsaData2_2.wVersion ) != 2 || HIBYTE( wsaData2_2.wVersion ) != 2 ) {
			WSACleanup();
			return; 
		}
	}

	if ( LOBYTE( wsaData1_1.wVersion ) != 1 || HIBYTE( wsaData1_1.wVersion ) != 1 ) {
			WSACleanup();
			return;
	}
}
 

執行結果：

Visual Leak Detector Version 2.5.1 installed.
wsa startup success. [1.1]
wsa startup success. [2.2]
No memory leaks detected.