DIRNAME(3)                 POSIX Programmer's Manual                DIRNAME(3)



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.


NNAAMMEE
       dirname -- report the parent directory name of a file pathname

SSYYNNOOPPSSIISS
       #include <libgen.h>

       char *dirname(char *_p_a_t_h);

DDEESSCCRRIIPPTTIIOONN
       The _d_i_r_n_a_m_e() function shall take a pointer to a character string that
       contains a pathname, and return a pointer to a string that is a
       pathname of the parent directory of that file. Trailing ''//'' characters
       in the path are not counted as part of the path.

       If _p_a_t_h does not contain a ''//'', then _d_i_r_n_a_m_e() shall return a pointer
       to the string "".."".  If _p_a_t_h is a null pointer or points to an empty
       string, _d_i_r_n_a_m_e() shall return a pointer to the string "".."".

       The _d_i_r_n_a_m_e() function need not be thread-safe.

RREETTUURRNN VVAALLUUEE
       The _d_i_r_n_a_m_e() function shall return a pointer to a string that is the
       parent directory of _p_a_t_h.  If _p_a_t_h is a null pointer or points to an
       empty string, a pointer to a string "".."" is returned.

       The _d_i_r_n_a_m_e() function may modify the string pointed to by _p_a_t_h, and
       may return a pointer to internal storage. The returned pointer might be
       invalidated or the storage might be overwritten by a subsequent call to
       _d_i_r_n_a_m_e().

EERRRROORRSS
       No errors are defined.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       The following code fragment reads a pathname, changes the current
       working directory to the parent directory, and opens the file.

           cchhaarr **ppaatthh == NNUULLLL,, **ppaatthhccooppyy;;
           ssiizzee__tt bbuufflleenn == 00;;
           ssssiizzee__tt lliinneelleenn == 00;;
           iinntt ffdd;;

           linelen = getline(&path, &buflen, stdin);

           path[linelen-1] = 0;
           pathcopy = strdup(path);
           if (chdir(dirname(pathcopy)) < 0) {
               ...
           }
           if ((fd = open(basename(path), O_RDONLY)) >= 0) {
               ...
               close (fd);
           }
           ...
           free (pathcopy);
           free (path);

   SSaammppllee IInnppuutt aanndd OOuuttppuutt SSttrriinnggss ffoorr ddiirrnnaammee(())
       In the following table, the input string is the value pointed to by
       _p_a_t_h, and the output string is the return value of the _d_i_r_n_a_m_e()
       function.

                           +-------------+---------------+
                           |IInnppuutt SSttrriinngg | OOuuttppuutt SSttrriinngg |
                           +-------------+---------------+
                           |"/usr/lib"   | "/usr"        |
                           |"/usr/"      | "/"           |
                           |"usr"        | "."           |
                           |"/"          | "/"           |
                           |"."          | "."           |
                           |".."         | "."           |
                           +-------------+---------------+
AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       The _d_i_r_n_a_m_e() and _b_a_s_e_n_a_m_e() functions together yield a complete
       pathname. The expression _d_i_r_n_a_m_e(_p_a_t_h) obtains the pathname of the
       directory where _b_a_s_e_n_a_m_e(_p_a_t_h) is found.

       Since the meaning of the leading ""////"" is implementation-defined,
       _d_i_r_n_a_m_e("////ffoooo) may return either ""////"" or ''//'' (but nothing else).

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _b_a_s_e_n_a_m_e()

       The Base Definitions volume of POSIX.1-2008, <<lliibbggeenn..hh>>

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2013                           DIRNAME(3)
