Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
PATHCONF(2)		  FreeBSD System Calls Manual		   PATHCONF(2)

NAME
     pathconf, fpathconf -- get	configurable pathname variables

SYNOPSIS
     #include <unistd.h>

     long
     pathconf(const char *path,	int name);

     long
     fpathconf(int fd, int name);

DESCRIPTION
     The pathconf() and	fpathconf() functions provide a	method for applica-
     tions 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
	     The maximum file link count.

     _PC_MAX_CANON
	     The maximum number	of bytes in a terminal canonical input line.

     _PC_MAX_INPUT
	     The maximum number	of bytes for which space is available in a
	     terminal input queue.

     _PC_NAME_MAX
	     The maximum number	of bytes in a file name.

     _PC_PATH_MAX
	     The maximum number	of bytes in a pathname.

     _PC_PIPE_BUF
	     The maximum number	of bytes which will be written atomically to a
	     pipe.

     _PC_CHOWN_RESTRICTED
	     Returns 1 if appropriate privileges are required for the chown(2)
	     system call, otherwise 0.	IEEE Std 1003.1-2001 ("POSIX.1") re-
	     quires appropriate	privilege in all cases,	but this behavior was
	     optional in prior editions	of the standard.

     _PC_NO_TRUNC
	     Returns 1 if attempts to use pathname components longer than
	     {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
	     Returns the terminal character disabling value.

     _PC_2_SYMLINKS
	     Returns 1 if the filesystem supports the creation of symbolic
	     links within the specified	directory; the meaning of
	     _PC_2_SYMLINKS is unspecified for non-directory files.

     _PC_ALLOC_SIZE_MIN
	     Minimum number of bytes of	storage	allocated for any portion of a
	     file.

     _PC_ASYNC_IO
	     Returns 1 if asynchronous I/O is supported, otherwise 0.

     _PC_FILESIZEBITS
	     Number of bits needed to represent	the maximum file size.

     _PC_PRIO_IO
	     Returns 1 if prioritized I/O is supported,	otherwise 0.

     _PC_REC_INCR_XFER_SIZE
	     Recommended increment for file transfer sizes between
	     _PC_REC_MIN_XFER_SIZE and _PC_REC_MAX_XFER_SIZE.

     _PC_REC_MAX_XFER_SIZE
	     Maximum recommended file transfer size.

     _PC_REC_MIN_XFER_SIZE
	     Minimum recommended file transfer size.

     _PC_REC_XFER_ALIGN
	     Recommended file transfer buffer alignment.

     _PC_SYMLINK_MAX
	     Maximum number of bytes in	a symbolic link.

     _PC_SYNC_IO
	     Returns 1 if synchronized I/O is supported, otherwise 0.

     _PC_TIMESTAMP_RESOLUTION
	     The resolution in nanoseconds of file timestamps.

RETURN VALUES
     If	the call to pathconf() or fpathconf() is not successful, -1 is re-
     turned and	errno is set appropriately.  Otherwise,	if the variable	is as-
     sociated 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.

ERRORS
     If	any of the following conditions	occur, the pathconf() and fpathconf()
     functions shall return -1 and set errno to	the corresponding value.

     [EINVAL]		The value of the name argument is invalid.

     [EINVAL]		The implementation does	not support an association of
			the variable name with the associated file.

     [EIO]		An I/O error occurred while reading from the file sys-
			tem.

     pathconf()	will fail if:

     [ENOTDIR]		A component of the path	prefix is not a	directory.

     [ENAMETOOLONG]	A component of a pathname exceeded NAME_MAX characters
			(but see _PC_NO_TRUNC above), or an entire pathname
			(including the terminating NUL)	exceeded PATH_MAX
			bytes.

     [ENOENT]		The named file does not	exist.

     [EACCES]		Search permission is denied for	a component of the
			path prefix.

     [ELOOP]		Too many symbolic links	were encountered in translat-
			ing the	pathname.

     [EFAULT]		path points outside the	process's allocated address
			space.

     fpathconf() will fail if:

     [EBADF]		fd is not a valid open file descriptor.

SEE ALSO
     sysctl(2),	sysconf(3)

STANDARDS
     The pathconf() and	fpathconf() functions conform to IEEE Std 1003.1-2008
     ("POSIX.1").

HISTORY
     The pathconf() and	fpathconf() functions first appeared in	4.4BSD.

FreeBSD	13.0			 June 21, 2018			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | HISTORY

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=pathconf&sektion=2&manpath=OpenBSD+6.9>

home | help