CODEWITHSUNDEEP
c++cwinapi
Mihran Hovsepyan
Mihran Hovsepyan

Reputation: 11108

How make FILE* from HANDLE in WinApi?

Is there easy way to create FILE* from WinApi HANDLE which points to one end of pipe? Something like we do in unix: fdopen(fd,<mode>);

Upvotes: 26

Views: 11681

Answers (3)

Greg Hewgill
Greg Hewgill

Reputation: 994927

You can do this but you have to do it in two steps. First, call _open_osfhandle() to get a C run-time file descriptor from a Win32 HANDLE value, then call _fdopen() to get a FILE* object from the file descriptor.

Upvotes: 33

max zhou
max zhou

Reputation: 51

FILE* getReadBinaryFile(LPCWSTR path) {
    HANDLE hFile = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hFile == INVALID_HANDLE_VALUE) { 
        return nullptr; 
    }
    int nHandle = _open_osfhandle((long)hFile, _O_RDONLY);
    if (nHandle == -1) { 
        ::CloseHandle(hFile);   //case 1
        return nullptr; 
    }
    FILE* fp = _fdopen(nHandle, "rb");
    if (!fp) {
        ::CloseHandle(hFile);  //case 2
    }
    return fp;
}

my code for get an open read binary file descriptor.

you should use fclose to close FILE* if you don't need it .

i didn't test for case 1 and 2, so use it at your own risk.

Upvotes: 4

fazo
fazo

Reputation: 1827

you can't exchange(convert) them.. if you need to have a file with FILE* and HANDLE you need to open it twice

Upvotes: -1

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