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. The _d_i_r_n_a_m_e() function
       shall not perform pathname resolution; the result shall not be affected
       by whether or not _p_a_t_h exists or by its file type. Trailing ''//''
       characters in the path that are not also leading ''//'' characters shall
       not be 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 may modify the string pointed to by _p_a_t_h, and
       may return a pointer to static storage that may then be overwritten by
       a subsequent call to _d_i_r_n_a_m_e().

       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 as described
       above.

       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().  The returned pointer might also be invalidated if the
       calling thread is terminated.

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.


           char *path = NULL, *pathcopy;
           size_t buflen = 0;
           ssize_t linelen = 0;
           int fd;

           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);

       The EXAMPLES section of the _b_a_s_e_n_a_m_e() function (see _b_a_s_e_n_a_m_e())
       includes a table showing examples of the results of processing several
       sample pathnames by the _b_a_s_e_n_a_m_e() and _d_i_r_n_a_m_e() functions and by the
       _b_a_s_e_n_a_m_e and _d_i_r_n_a_m_e utilities.

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.1-2017, <<lliibbggeenn..hh>>

       The Shell and Utilities volume of POSIX.1-2017, _b_a_s_e_n_a_m_e, _d_i_r_n_a_m_e

CCOOPPYYRRIIGGHHTT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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                  2017                           DIRNAME(3)
