DIRNAME(3C) Standard C Library Functions DIRNAME(3C)

NAME

dirname - report the parent directory name of a file path name

SYNOPSIS

#include <libgen.h>

char *dirname(char *path);

DESCRIPTION

The dirname() function takes a pointer to a character string that
contains a pathname, and returns 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() returns a pointer to the
string "." . If path is a null pointer or points to an empty string,
dirname() returns a pointer to the string "." .

RETURN VALUES

The dirname() function returns 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.

ERRORS

No errors are defined.

EXAMPLES

Example 1: Changing the Current Directory to the Parent Directory.

The following code fragment reads a pathname, changes the current working
directory to the parent directory of the named file (see chdir(2)), and
opens the file.


char path[[MAXPATHLEN], *pathcopy;
int fd;
fgets(path, MAXPATHLEN, stdin);
pathcopy = strdup(path);
chdir(dirname(pathcopy));
fd = open(basename(path), O_RDONLY);

Example 2: 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" | "/" |
+-------------+---------------+
|"/" | "/" |
+-------------+---------------+
|"." | "." |
+-------------+---------------+
|".." | "." |
+-------------+---------------+

USAGE

The dirname() function modifies the string pointed to by path.


The dirname() and basename(3C) functions together yield a complete
pathname. The expression dirname(path) obtains the pathname of the
directory where basename(path) is found.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

basename(1), chdir(2), basename(3C), attributes(7), standards(7)

March 18, 2002 DIRNAME(3C)