如何确保fopen（）在未连接到网络时不会阻塞？

My win32 C++ application frequently checks a file that normally resides on a network share [in our corporate network]. But if the computer isn't connected to a network, the application freezes for several minutes and the user usually has to end the process. How can I check if the file is accessible before I open it?My win32 C++ application frequently checks a fi