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
     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 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
     variable 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
                        translating 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
     getconf(1), confstr(3), sysconf(3), sysctl(3)

HISTORY
     The pathconf() and fpathconf() functions first appeared in 4.4BSD.  The
     lpathconf() system call first appeared in DragonFly 3.5.

DragonFly 5.5-DEVELOPMENT        May 12, 2019        DragonFly 5.5-DEVELOPMENT