fpathconf man page

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).

InterfaceAttributeValue
fpathconf(), pathconf()Thread safetyMT-Safe

Conforming to

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 4.08 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/.

Referenced By

confstr(3), explain(1), explain(3), explain_fpathconf(3), explain_fpathconf_or_die(3), explain_lca2010(1), explain_pathconf(3), explain_pathconf_or_die(3), getcwd(3), nfs(5), posixoptions(7), procenv(1), realpath(3), sysconf(3).

pathconf(3) is an alias of fpathconf(3).

2015-08-08 GNU Linux Programmer's Manual