PATHCONF(2) | System Calls Manual | PATHCONF(2) |
pathconf
,
fpathconf
— get configurable
pathname variables
#include
<unistd.h>
long
pathconf
(const
char *path, int
name);
long
fpathconf
(int
fd, int name);
The
pathconf
()
and
fpathconf
()
functions 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.
For
pathconf
(),
the path argument is the name of a file or directory.
For
fpathconf
(),
the fd argument is an open file descriptor. The
name argument specifies the system variable to be
queried. Symbolic constants for each name value are found in the include
file <unistd.h>
.
The available values are as follows:
_PC_LINK_MAX
_PC_MAX_CANON
_PC_MAX_INPUT
_PC_NAME_MAX
_PC_PATH_MAX
_PC_PIPE_BUF
_PC_CHOWN_RESTRICTED
_PC_NO_TRUNC
NAME_MAX
} will result in an
[ENAMETOOLONG
] error; otherwise, such components
will be truncated to {NAME_MAX
}.
IEEE Std 1003.1-2001 (“POSIX.1”)
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
_PC_2_SYMLINKS
_PC_2_SYMLINKS
is unspecified for non-directory
files._PC_ALLOC_SIZE_MIN
_PC_ASYNC_IO
_PC_FILESIZEBITS
_PC_PRIO_IO
_PC_REC_INCR_XFER_SIZE
_PC_REC_MAX_XFER_SIZE
_PC_REC_MIN_XFER_SIZE
_PC_REC_XFER_ALIGN
_PC_SYMLINK_MAX
_PC_SYNC_IO
_PC_TIMESTAMP_RESOLUTION
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
()
functions shall return -1 and set errno to the
corresponding value.
EINVAL
]EINVAL
]EIO
]pathconf
() will fail if:
ENOTDIR
]ENAMETOOLONG
]NAME_MAX
characters (but see _PC_NO_TRUNC
above), or an
entire pathname (including the terminating NUL) exceeded
PATH_MAX
bytes.ENOENT
]EACCES
]ELOOP
]EFAULT
]fpathconf
() will fail if:
EBADF
]The pathconf
() and
fpathconf
() functions conform to
IEEE Std 1003.1-2008 (“POSIX.1”).
The pathconf
() and
fpathconf
() functions first appeared in
4.4BSD.
May 31, 2015 | OpenBSD-6.1 |