See GetRtFileInfoByHandle

typedef struct tagFileInfoStandard {
        QWORD           qwFileSize;
        QWORD           qwFileAllocationSize;
        DWORD           dwNumberOfLinks;
        BOOLEAN         bDirectory;
        BOOLEAN         _unused[3];
} FILE_INFO_STANDARD;

Fields

qwFileSize

The size of the file in bytes.

qwFileAllocationSize

The amount of disk space consumed by the file, in bytes.

dwNumberOfLinks

(current unused)

bDirectory

Contains a non-zero value if the file is a directory, else 0.