pathconf(3)
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 │ └────────────────────────┴───────────────┴─────────┘
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 4.09 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/.
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