[OpenBSD]

Manual Page Search Parameters
dirname(3) extract the directory portion of a pathname
File::Basename, basename, dirname, fileparse(3p) Parse file paths into directory, filename and suffix.

DIRNAME(3) Library Functions Manual DIRNAME(3)

dirname
extract the directory portion of a pathname

#include <libgen.h>
char *
dirname(const char *path);

The dirname() function is the converse of basename(3); it returns a pointer to the parent directory of the pathname pointed to by path. Any trailing ‘/’ characters are not counted as part of the directory name. If path is a null pointer, the empty string, or contains no ‘/’ characters, dirname() returns a pointer to the string “.”, signifying the current directory.

On successful completion, dirname() returns a pointer to the parent directory of path.
If dirname() fails, a null pointer is returned and the global variable errno is set to indicate the error.

The following error codes may be set in errno:
 
 
[]
The path component to be returned was larger than PATH_MAX.

basename(1), dirname(1), basename(3)

The dirname() function conforms to the X/Open System Interfaces option of the IEEE Std 1003.1-2008 (“POSIX.1”) specification.

The dirname() function first appeared in OpenBSD 2.2.

Todd C. Miller

dirname() returns a pointer to internal static storage space that will be overwritten by subsequent calls (each function has its own separate storage).
Other vendor implementations of dirname() may modify the contents of the string passed to dirname(); this should be taken into account when writing code which calls this function if portability is desired.
May 8, 2017 OpenBSD-current