stat64

stat64 is a platform-specific variant of the POSIX stat facility used to obtain metadata about files and file descriptors. It differs from the traditional stat interface by providing 64-bit fields for file size and block counts, enabling support for files larger than 2 GiB on systems where the default off_t and related types are 32-bit.

The stat64 interface typically includes the same kinds of members as stat: device and inode identifiers, file mode and permissions, link count, owner and group IDs, special device ID for character/block devices, file size, preferred I/O block size, allocated block count, and timestamps for last access, modification, and status change. Some implementations offer nanosecond-resolution timestamp fields or extended attributes.

stat64 and its companions (fstat64, lstat64) were introduced as part of Large File Support (LFS) on 32-bit Unix-like systems. On many modern systems, especially 64-bit ones, the normal stat already uses 64-bit offsets; on others the feature is enabled by defining platform macros (for example _FILE_OFFSET_BITS=64 on many Unix implementations), which transparently map stat to stat64. On Microsoft C runtimes a similar facility exists under names like _stat64.

Because contemporary interfaces and standards have evolved, developers are encouraged to use the canonical interfaces or platform-recommended mechanisms (such as enabling LFS macros or using newer APIs like statx on Linux) for portability and future compatibility.