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pathconf(2)                 BSD System Calls Manual                pathconf(2)


     fpathconf, pathconf -- get configurable pathname variables


     #include <unistd.h>

     fpathconf(int fildes, int name);

     pathconf(const char *path, int name);


     The pathconf() and fpathconf() functions provides 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 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:

             The maximum file link count.

             The maximum number of bytes in terminal canonical input line.

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

             The maximum number of bytes in a file name.

             The maximum number of bytes in a pathname.

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

             Return 1 if appropriate privileges are required for the chown(2)
             system call, otherwise 0.

             Return 1 if file names longer than KERN_NAME_MAX are truncated.

             Returns the terminal character disabling value.

             Returns the number of bits used to store maximum extended
             attribute size in bytes.  For example, 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.


     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.


     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.

     Pathconf() will fail if:

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

     [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 loop-
                     ing 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.




     The pathconf and fpathconf functions first appeared in 4.4BSD.

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

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