DragonFly On-Line Manual Pages


PATHCONF(2)		 DragonFly System Calls Manual		   PATHCONF(2)

NAME

pathconf, lpathconf, fpathconf -- get configurable pathname variables

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <unistd.h> long pathconf(const char *path, int name); long lpathconf(const char *path, int name); long fpathconf(int fd, int name);

DESCRIPTION

The pathconf(), lpathconf() 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() and lpathconf(), the path argument is the name of a file or directory. For fpathconf(), the fd argument is an open file descrip- tor. 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 lpathconf() system call is like pathconf() except in the case where the named file is a symbolic link, in which case lpathconf() returns information about the link, while pathconf() returns information about the file the link references. The available values are as follows: _PC_LINK_MAX The maximum file link count. _PC_MAX_CANON The maximum number of bytes in terminal canonical input line. _PC_MAX_INPUT The minimum 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 Return 1 if appropriate privileges are required for the chown(2) system call, otherwise 0. _PC_NO_TRUNC Return 1 if file names longer than KERN_NAME_MAX are truncated. _PC_VDISABLE Returns the terminal character disabling value.

RETURN VALUES

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 vari- able value is returned.

ERRORS

If any of the following conditions occur, the pathconf(), lpathconf() 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. Pathconf() and lpathconf() will fail if: [ENOTDIR] A component of the path prefix is not a directory. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [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. [EIO] An I/O error occurred while reading from or writing to the file system. Fpathconf() will fail if: [EBADF] fd is not a valid open file descriptor. [EIO] An I/O error occurred while reading from or writing to the file system.

SEE ALSO

sysctl(3)

HISTORY

The pathconf() and fpathconf() functions first appeared in 4.4BSD. The lpathconf() system call first appeared in DragonFly 3.5. DragonFly 3.7 April 13, 2013 DragonFly 3.7