Updated: May 06, 2022

Shared object that supports Apple Macintosh HFS and HFS Plus (QNX Neutrino)


driver … mac mac_options… &

Runs on:

QNX Neutrino


The driver is any of the devb-* drivers, and mac_options is one or more of the following, separated by commas:

Set the handling of HFS+ symbolic links. The options are:
  • ignore — treat a symlink as a regular file, but remove any execute permissions.
  • all — if a segment of a path is a symlink, replace the segment with the symlink's content (the default).

In addition, you can specify any of the filesystem options described for io-blk.so.


The fs-mac.so shared object provides read-only support for Apple HFS (Hierarchical File System) and HFS Plus. It's automatically loaded by the devb-* drivers when mounting an Apple filesystem.

Note: This filesystem uses UTF-8 encoding for presentation of its filenames; attempts to specify a filename not using UTF-8 encoding will fail (with an error of EILSEQ).

The slash (/) character (which is valid in file names on the Mac but not in POSIX) is swapped with the colon (:) (which is the Mac path separator). For example, an HFS file called 29/1/2009 will get shown to ls as 29:1:2009, and when opened with that name will internally match back to the 29/1/2009 on-disk name.

The fs-mac.so shared object doesn't support access to the resource fork or hard links.

Summary of filesystem commands

The following table shows the shared objects and related commands for the filesystems:

Partition type Filesystem Shared object Initialize with: Check with:
1, 4, or 6 DOS fs-dos.so mkdosfs chkdosfs
7 Windows NTa fs-nt.so N/A N/A
11, 12, or 14 FAT32 fs-dos.so mkdosfs chkdosfs
77, 78, or 79 QNX 4 N/A N/A N/A
131 Linux (Ext2) fs-ext2.so N/A N/A
175 Apple Macintosh HFS or HFS Plusa fs-mac.so N/A N/A
177, 178, or 179 Power-Safe fs-qnx6.so mkqnx6fs chkqnx6fsb
185 QNX Trusted Disk fs-qtd.so mkqfs N/A

a Read-only.

b Not usually necessary.

For more information, see the Filesystems chapter of the System Architecture guide.