fpathconf(2) SYSTEM CALLS fpathconf(2)
NAME
fpathconf, pathconf - get configurable pathname variables
SYNOPSIS
#include <unistd.h>
long fpathconf (int fildes, int name);
long pathconf (char *path, int name);
DESCRIPTION
The functions fpathconf and pathconf return the current
value of a configurable limit or option associated with a
file or directory. The path argument points to the pathname
of a file or directory; fildes is an open file descriptor;
and name is the symbolic constant (defined in <unistd.h>)
representing the configurable system limit or option to be
returned.
The values returned by pathconf and fpathconf depend on the
type of file specified by path or fildes. The following
table contains the symbolic constants supported by pathconf
and fpathconf along with the POSIX defined return value.
The return value is based on the type of file specified by
path or fildes.
___________________________________
| Value of name | See Note|
|______________________|___________|
|______________________|___________|
| PCLINKMAX | 1 |
|______________________|___________|
| PCMAXCANNON | 2 |
|______________________|___________|
| PCMAXINPUT | 2 |
|______________________|___________|
| PCNAMEMAX | 3,4 |
|______________________|___________|
| PCPATHMAX | 4,5 |
|______________________|___________|
| PCPIPEBUF | 6 |
|______________________|___________|
| PCCHOWNRESTRICTED | 7 |
|______________________|___________|
| PCNOTRUNC | 3,4 |
|______________________|___________|
| PCVDISABLE | 2 |
|______________________|___________|
Notes:
1 If path or fildes refers to a directory, the value
returned applies to the directory itself.
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fpathconf(2) SYSTEM CALLS fpathconf(2)
2 The behavior is undefined if path or fildes does not
refer to a terminal file.
3 If path or fildes refers to a directory, the value
returned applies to the filenames within the directory.
4 The behavior is undefined if path or fildes does not
refer to a directory.
5 If path or fildes refers to a directory, the value
returned is the maximum length of a relative pathname
when the specified directory is the working directory.
6 If path or fildes refers to a pipe or FIFO, the value
returned applies to the FIFO itself. If path or fildes
refers to a directory, the value returned applies to
any FIFOs that exist or can be created within the
directory. If path or fildes refer to any other type
of file, the behavior is undefined.
7 If path or fildes refers to a directory, the value
returned applies to any files, other than directories,
that exist or can be created within the directory.
The value of the configurable system limit or option speci-
fied by name does not change during the lifetime of the cal-
ling process.
fpathconf fails if the following is true:
EBADF fildes is not a valid file descriptor.
pathconf fails if one or more of the following are true:
EACCES search permission is denied for a component of the
path prefix.
ELOOP too many symbolic links are encountered while
translating path.
EMULTIHOP
components of path require hopping to multiple remote
machines and file system type does not allow it.
ENAMETOOLONG
the length of a pathname exceeds {PATHMAX}, or path-
name component is longer than {NAMEMAX} while
(POSIXNOTRUNC) is in effect.
ENOENT path is needed for the command specified and the
named file does not exist or if the path argument
points to an empty string.
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fpathconf(2) SYSTEM CALLS fpathconf(2)
ENOLINKpath points to a remote machine and the link to that
machine is no longer active.
ENOTDIRa component of the path prefix is not a directory.
Both fpathconf and pathconf fail if the following is true:
EINVAL if name is an invalid value.
SEE ALSO
sysconf(3C), limits(4)
DIAGNOSTICS
If fpathconf or pathconf are invoked with an invalid sym-
bolic constant or the symbolic constant corresponds to a
configurable system limit or option not supported on the
system, a value of -1 is returned to the invoking process.
If the function fails because the configurable system limit
or option corresponding to name is not supported on the sys-
tem the value of errno is not changed.
3