pathconf(2freebsd)

pathconf, lpathconf, fpathconf - get configurable pathname variables

.Lb libc

.In unistd.h long pathconf const char *path int name long lpathconf const char *path int name long fpathconf int fd int name

The pathconf, lpathconf and fpathconf system calls provide a method for applications to determine the current value of a configurable system limit or option variable associated with a pathname or file descriptor.

_PC_LINK_MAX
	The maximum file link count.
_PC_MAX_CANON
	The maximum number of bytes in terminal canonical input line.
_PC_MAX_INPUT
	The minimum maximum number of bytes for which space is available in a terminal input queue.
_PC_NAME_MAX
	The maximum number of bytes in a file name.
_PC_PATH_MAX
	The maximum number of bytes in a pathname.
_PC_PIPE_BUF
	The maximum number of bytes which will be written atomically to a pipe.
_PC_CHOWN_RESTRICTED
	Return 1 if appropriate privilege is required for the chown(2) system call, otherwise 0. -p1003.1-2001 requires appropriate privilege in all cases, but this behavior was optional in prior editions of the standard.
_PC_NO_TRUNC
	Return greater than zero if attempts to use pathname components longer than .Brq Dv NAME_MAX will result in an [ENAMETOOLONG] error; otherwise, such components will be truncated to .Brq Dv NAME_MAX . -p1003.1-2001 requires the error in all cases, but this behavior was optional in prior editions of the standard, and some non- POSIX -compliant file systems do not support this behavior.
_PC_VDISABLE
	Returns the terminal character disabling value.
_PC_ASYNC_IO
	Return 1 if asynchronous I/O is supported, otherwise 0.
_PC_PRIO_IO
	Returns 1 if prioritised I/O is supported for this file, otherwise 0.
_PC_SYNC_IO
	Returns 1 if synchronised I/O is supported for this file, otherwise 0.
_PC_ALLOC_SIZE_MIN
	Minimum number of bytes of storage allocated for any portion of a file.
_PC_FILESIZEBITS
	Number of bits needed to represent the maximum file size.
_PC_REC_INCR_XFER_SIZE
	Recommended increment for file transfer sizes between _PC_REC_MIN_XFER_SIZE and _PC_REC_MAX_XFER_SIZE.
_PC_REC_MAX_XFER_SIZE
	Maximum recommended file transfer size.
_PC_REC_MIN_XFER_SIZE
	Minimum recommended file transfer size.
_PC_REC_XFER_ALIGN
	Recommended file transfer buffer alignment.
_PC_SYMLINK_MAX
	Maximum number of bytes in a symbolic link.
_PC_ACL_EXTENDED
	Returns 1 if an Access Control List (ACL) can be set on the specified file, otherwise 0.
_PC_ACL_NFS4
	Returns 1 if an NFSv4 ACLs can be set on the specified file, otherwise 0.
_PC_ACL_PATH_MAX
	Maximum number of ACL entries per file.
_PC_CAP_PRESENT
	Returns 1 if a capability state can be set on the specified file, otherwise 0.
_PC_INF_PRESENT
	Returns 1 if an information label can be set on the specified file, otherwise 0.
_PC_MAC_PRESENT
	Returns 1 if a Mandatory Access Control (MAC) label can be set on the specified file, otherwise 0.
_PC_MIN_HOLE_SIZE
	If a file system supports the reporting of holes (see lseek(2)), pathconf and fpathconf return a positive number that represents the minimum hole size returned in bytes. The offsets of holes returned will be aligned to this same value. A special value of 1 is returned if the file system does not specify the minimum hole size but still reports holes.

If the call to pathconf or fpathconf is not successful, -1 is returned and errno is set appropriately. Otherwise, if the variable is associated with functionality that does not have a limit in the system, -1 is returned and errno is not modified. Otherwise, the current variable value is returned.

If any of the following conditions occur, the pathconf and fpathconf system calls shall return -1 and set errno to the corresponding value.

[EINVAL]
	The value of the name argument is invalid.
[EINVAL]
	The implementation does not support an association of the variable name with the associated file.

[ENOTDIR]
	A component of the path prefix is not a directory.
[ENAMETOOLONG]
	A component of a pathname exceeded .Brq Dv NAME_MAX characters (but see _PC_NO_TRUNC above), or an entire path name exceeded .Brq Dv PATH_MAX characters.
[ENOENT]
	The named file does not exist.
[EACCES]
	Search permission is denied for a component of the path prefix.
[ELOOP]
	Too many symbolic links were encountered in translating the pathname.
[EIO]	An I/O error occurred while reading from or writing to the file system.

[EBADF]
	The fd argument is not a valid open file descriptor.
[EIO]	An I/O error occurred while reading from or writing to the file system.

lseek(2), sysctl(3)

The pathconf and fpathconf system calls first appeared in BSD 4.4 . The lpathconf system call first appeared in
.Fx 8.0 .