NAME¶
fpathconf, pathconf - get configuration values for files
SYNOPSIS¶
#include <unistd.h>
long fpathconf(int fd, int name);
long pathconf(const char *path, int name);
DESCRIPTION¶
fpathconf() gets a value for the configuration option
name for the
open file descriptor
fd.
pathconf() gets a value for configuration option
name for the
filename
path.
The corresponding macros defined in
<unistd.h> are minimum values;
if an application wants to take advantage of values which may change, a call
to
fpathconf() or
pathconf() can be made, which may yield more
liberal results.
Setting
name equal to one of the following constants returns the
following configuration options:
- _PC_LINK_MAX
- returns the maximum number of links to the file. If fd or
path refer to a directory, then the value applies to the whole
directory. The corresponding macro is _POSIX_LINK_MAX.
- _PC_MAX_CANON
- returns the maximum length of a formatted input line, where fd or
path must refer to a terminal. The corresponding macro is
_POSIX_MAX_CANON.
- _PC_MAX_INPUT
- returns the maximum length of an input line, where fd or
path must refer to a terminal. The corresponding macro is
_POSIX_MAX_INPUT.
- _PC_NAME_MAX
- returns the maximum length of a filename in the directory path or
fd that the process is allowed to create. The corresponding macro
is _POSIX_NAME_MAX.
- _PC_PATH_MAX
- returns the maximum length of a relative pathname when path or
fd is the current working directory. The corresponding macro is
_POSIX_PATH_MAX.
- _PC_PIPE_BUF
- returns the size of the pipe buffer, where fd must refer to a pipe
or FIFO and path must refer to a FIFO. The corresponding macro is
_POSIX_PIPE_BUF.
- _PC_CHOWN_RESTRICTED
- returns nonzero if the chown(2) call may not be used on this file.
If fd or path refer to a directory, then this applies to all
files in that directory. The corresponding macro is
_POSIX_CHOWN_RESTRICTED.
- _PC_NO_TRUNC
- returns nonzero if accessing filenames longer than _POSIX_NAME_MAX
generates an error. The corresponding macro is
_POSIX_NO_TRUNC.
- _PC_VDISABLE
- returns nonzero if special character processing can be disabled, where
fd or path must refer to a terminal.
RETURN VALUE¶
The limit is returned, if one exists. If the system does not have a limit for
the requested resource, -1 is returned, and
errno is unchanged. If
there is an error, -1 is returned, and
errno is set to reflect the
nature of the error.
ATTRIBUTES¶
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
fpathconf (), pathconf () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008.
NOTES¶
Files with name lengths longer than the value returned for
name equal to
_PC_NAME_MAX may exist in the given directory.
Some returned values may be huge; they are not suitable for allocating memory.
SEE ALSO¶
getconf(1),
open(2),
statfs(2),
confstr(3),
sysconf(3)
COLOPHON¶
This page is part of release 4.10 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
https://www.kernel.org/doc/man-pages/.