Module dio_align 

Available on crate features async and polars-io only.

O_DIRECT alignment discovery.

O_DIRECT requires the file offset, the transfer length, and the buffer address to be aligned.

Sources, in order of accuracy:

1. statx(STATX_DIOALIGN) (Linux 6.1+) - authoritative, per-file, and distinguishes memory alignment from offset/length alignment. It can also say definitively that a file does not support direct I/O. Only available on glibc: libc does not expose statx on musl.
2. /sys/dev/block/<major>:<minor>/queue/logical_block_size - the device sector size. Right for most filesystems, but misses cases where the filesystem imposes something stricter.

When neither can answer, the alignment stays unknown and the caller reads through the page cache.

Structs

DioAlign