GETFSSTAT(2) System Calls Manual GETFSSTAT(2)

getfsstat — get list of all mounted file systems

#include <sys/param.h>
#include <sys/ucred.h>
#include <sys/mount.h>

int
getfsstat(struct statfs *buf, int bufsize, int flags);

int
(struct statfs64 *buf, int bufsize, int flags);

The () function returns information about all mounted file systems. The buf argument is a pointer to an array of statfs structures (see statfs(2)). As statfs(2) indicates, the structure is defined differently depending on whether the macro _DARWIN_FEATURE_64_BIT_INODE is defined (see stat(2) for more information on this macro).

Fields that are undefined for a particular file system are set to -1. The buffer is filled with an array of statfs structures, one for each mounted file system up to the size specified by bufsize.

If buf is given as NULL, () returns just the number of mounted file systems.

If flags is set to MNT_NOWAIT, () will directly return the information retained in the kernel to avoid delays caused by waiting for updated information from a file system that is perhaps temporarily unable to respond. Some of the information returned may be out of date, however; if flags is set to MNT_WAIT or MNT_DWAIT instead, getfsstat() will request updated information from each mounted filesystem before returning.

Upon successful completion, the number of statfs structures is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

getfsstat() fails if one or more of the following are true:

[]
The buf argument points to an invalid address.
[]
An I/O error occurred while reading from or writing to the file system.

The getfsstat64() routine is equivalent to the default () (when _DARWIN_FEATURE_64_BIT_INODE is defined), so there is no longer any reason to use it (it will be removed in the future).

stat(2), statfs(2), fstab(5), mount(8)

The getfsstat() function first appeared in 4.4BSD.

October 28, 2008 macOS 15.2