Man Pages

dirname(3p) - phpMan dirname(3p) - phpMan

Command: man perldoc info search(apropos)  


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



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (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 reentrant. A function that is not required to be reentrant is  not  required
       to 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  static  storage
       that may then be overwritten by subsequent calls 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[PATH_MAX], *pathcopy;
              int fd;
              fgets(path, PATH_MAX, stdin);
              pathcopy = strdup(path);
              chdir(dirname(pathcopy));
              fd = open(basename(path), O_RDONLY);

   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"          "."
                                                "/"            "/"
                                                "."            "."
                                                ".."           "."

   Changing the Current Directory to the Parent Directory
       The following program fragment reads a pathname, changes the current working directory to the parent directory,
       and opens the file.


              #include <unistd.h>
              #include <limits.h>
              #include <stdio.h>
              #include <fcntl.h>
              #include <string.h>
              #include <libgen.h>
              ...
              char path[PATH_MAX], *pathcopy;
              int fd;
              ...
              fgets(path, PATH_MAX, stdin);
              pathcopy = strdup(path);
              chdir(dirname(pathcopy));
              fd = open(basename(path), O_RDONLY);

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 IEEE Std 1003.1-2001, <libgen.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions Issue 6, Copyright (C) 2001-2003 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 Stan-
       dard, 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 .



IEEE/The Open Group                  2003                          DIRNAME(3P)