具有2个参数的Typedef指向WINAPI函数的指针

Question

What does this mean? I know that NtUnMapViewOfSection is a pointer to a Winapi function with 2 parameters and a long return value. And I know that this chunk is casting "GetProcAddress" with its arguments to a NtUnmapViewOfSection object. But what is the last row doing?

typedef LONG (WINAPI * NtUnmapViewOfSection)(HANDLE ProcessHandle, PVOID BaseAddress);

NtUnmapViewOfSection xNtUnmapViewOfSection;
xNtUnmapViewOfSection = NtUnmapViewOfSection(GetProcAddress(GetModuleHandleA("ntdll.dll"), "NtUnmapViewOfSection"));
xNtUnmapViewOfSection(Pinfo.hProcess, PVOID(dwImageBase)); // Pinfo is PROCESS_INFORMATION and dwImageBase is a pointer to DWORD

Answer 1

what is the last row doing?

The last line is calling the function you got a pointer to with GetProcAddress() - that is, it is calling NtUnmapViewOfSection() .