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BASENAME(3)                Linux Programmer's Manual               BASENAME(3)



NAME
       basename, dirname - parse pathname components

SYNOPSIS
       #include <libgen.h>

       char *dirname(char *path);

       char *basename(char *path);

DESCRIPTION
       Warning: there are two different functions basename() - see below.

       The functions dirname() and basename() break a null-terminated pathname string into directory and filename com-
       ponents.  In the usual case, dirname() returns the string up to, but not including, the final  '/',  and  base-
       name()  returns  the component following the final '/'.  Trailing '/' characters are not counted as part of the
       pathname.

       If path does not contain a slash, dirname() returns the string "." while basename() returns a copy of path.  If
       path is the string "/", then both dirname() and basename() return the string "/".  If path is a NULL pointer or
       points to an empty string, then both dirname() and basename() return the string ".".

       Concatenating the string returned by dirname(), a "/", and the string returned by basename() yields a  complete
       pathname.

       Both dirname() and basename() may modify the contents of path, so it may be desirable to pass a copy when call-
       ing one of these functions.

       These functions may return pointers to statically allocated memory  which  may  be  overwritten  by  subsequent
       calls.   Alternatively,  they may return a pointer to some part of path, so that the string referred to by path
       should not be modified or freed until the pointer returned by the function is no longer required.

       The following list of examples (taken from SUSv2) shows the strings returned by dirname()  and  basename()  for
       different paths:

       path         dirname    basename
       "/usr/lib"    "/usr"    "lib"
       "/usr/"       "/"       "usr"
       "usr"         "."       "usr"
       "/"           "/"       "/"
       "."           "."       "."
       ".."          "."       ".."

RETURN VALUE
       Both  dirname()  and  basename()  return  pointers  to null-terminated strings.  (Do not pass these pointers to
       free(3).)

CONFORMING TO
       POSIX.1-2001.

NOTES
       There are two different versions of basename() - the POSIX version described above, and the GNU version,  which
       one gets after

           #define _GNU_SOURCE
           #include <string.h>

       The  GNU  version never modifies its argument, and returns the empty string when path has a trailing slash, and
       in particular also when it is "/".  There is no GNU version of dirname().

       With glibc, one gets the POSIX version of basename() when <libgen.h> is included, and the  GNU  version  other-
       wise.

BUGS
       In  the  glibc implementation of the POSIX versions of these functions they modify their argument, and segfault
       when called with a static string like "/usr/".  Before glibc 2.2.1, the glibc version of dirname() did not cor-
       rectly handle pathnames with trailing '/' characters, and generated a segfault if given a NULL argument.

EXAMPLE
           char *dirc, *basec, *bname, *dname;
           char *path = "/etc/passwd";

           dirc = strdup(path);
           basec = strdup(path);
           dname = dirname(dirc);
           bname = basename(basec);
           printf("dirname=%s, basename=%s\n", dname, bname);

SEE ALSO
       basename(1), dirname(1), feature_test_macros(7)

COLOPHON
       This  page  is part of release 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



GNU                               2009-03-30                       BASENAME(3)