PROLOG

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

NAME

       dirname — report the parent directory name of a file pathname

SYNOPSIS

       #include <libgen.h>

       char *dirname(char *path);

DESCRIPTION

       The  dirname()  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 dirname() function shall not perform pathname resolution; the result shall
       not be affected by whether or not path 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 path does not contain a '/', then dirname() shall return a pointer to the  string  ".".
       If  path  is a null pointer or points to an empty string, dirname() shall return a pointer
       to the string ".".

       The dirname() function may modify the string pointed to by path, and may return a  pointer
       to static storage that may then be overwritten by a subsequent call to dirname().

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

RETURN VALUE

       The dirname() function shall return a pointer to a string as described above.

       The  dirname() function may modify the string pointed to by path, 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  dirname().   The  returned pointer might also be
       invalidated if the calling thread is terminated.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       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 basename() function (see basename()) includes a table showing
       examples of the results of processing several  sample  pathnames  by  the  basename()  and
       dirname() functions and by the basename and dirname utilities.

APPLICATION USAGE

       The  dirname() and basename() functions together yield a complete pathname. The expression
       dirname(path) obtains the pathname of the directory where basename(path) is found.

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

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       basename()

       The Base Definitions volume of POSIX.1‐2017, <libgen.h>

       The Shell and Utilities volume of POSIX.1‐2017, basename, dirname

COPYRIGHT

       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 .