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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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DIRNAME(3P) POSIX Programmer's Manual DIRNAME(3P)
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.
dirname — report the parent directory name of a file pathname
#include <libgen.h>
char *dirname(char *path);
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.
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.
No errors are defined.
The following sections are informative.
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(3p))
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.
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).
None.
None.
basename(3p)
The Base Definitions volume of POSIX.1‐2017, libgen.h(0p)
The Shell and Utilities volume of POSIX.1‐2017, basename(1p),
dirname(1p)
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 .
IEEE/The Open Group 2017 DIRNAME(3P)
Pages that refer to this page: libgen.h(0p), basename(1p), dirname(1p), basename(3p)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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