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PATHCONF(2)                 BSD System Calls Manual                PATHCONF(2)

NAME
     fpathconf, pathconf -- get configurable pathname variables

SYNOPSIS
     #include <unistd.h>

     long
     fpathconf(int fildes, int name);

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

DESCRIPTION
     The pathconf() and fpathconf() functions provides 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, the path argument is the name of a file or directory.  For fpathconf, the fildes 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 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.

     _PC_XATTR_SIZE_BITS
             Returns the number of bits used to store maximum extended attribute size in bytes.  For exam-ple, example,
             ple, if the maximum attribute size supported by a file system is 128K, the value returned will
             be 18.  However a value 18 can mean that the maximum attribute size can be anywhere from (256KB
             - 1) to 128KB.  As a special case, the resource fork can have much larger size, and some file
             system specific extended attributes can have smaller and preset size; for example, Finder Info
             is always 32 bytes.

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 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 asso-ciated associated
                     ciated file.

     Pathconf() will fail if:

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

     [EIO]           An I/O error occurs while reading from or writing to the file system.

     [ELOOP]         Too many symbolic links are encountered in translating the pathname.  This is taken to
                     be indicative of a looping symbolic link.

     [ENAMETOOLONG]  A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023
                     characters.

     [ENOENT]        The named file does not exist.

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

     Fpathconf() will fail if:

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

     [EIO]           An I/O error occurs while reading from or writing to the file system.

SEE ALSO
     sysctl(3)

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

4th Berkeley Distribution        June 4, 1993        4th Berkeley Distribution