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. Trailing '/' characters in the path are not 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 need not be thread-safe.

RETURN VALUE

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

       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().

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);

   Sample Input and Output Strings for dirname()
       In the following table, the input string is the value pointed to by path, and  the  output
       string is the return value of the dirname() function.

                                     ┌─────────────┬───────────────┐
                                     │Input String │ Output String │
                                     ├─────────────┼───────────────┤
                                     │"/usr/lib"   │ "/usr"        │
                                     │"/usr/"      │ "/"           │
                                     │"usr"        │ "."           │
                                     │"/"          │ "/"           │
                                     │"."          │ "."           │
                                     │".."         │ "."           │
                                     └─────────────┴───────────────┘

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.1‐2008, <libgen.h>

COPYRIGHT

       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 .