The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2003 Edition
Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.

NAME

basename - return the last component of a pathname

SYNOPSIS

[XSI] [Option Start] #include <libgen.h>

char *basename(char *
path); [Option End]

DESCRIPTION

The basename() function shall take the pathname pointed to by path and return a pointer to the final component of the pathname, deleting any trailing '/' characters.

If the string consists entirely of the '/' character, basename() shall return a pointer to the string "/" . If the string is exactly "//" , it is implementation-defined whether '/' or "//" is returned.

If path is a null pointer or points to an empty string, basename() shall return a pointer to the string "." .

The basename() 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 basename().

The basename() function need not be reentrant. A function that is not required to be reentrant is not required to be thread-safe.

RETURN VALUE

The basename() function shall return a pointer to the final component of path.

ERRORS

No errors are defined.


The following sections are informative.

EXAMPLES

Using basename()

The following program fragment returns a pointer to the value lib, which is the base name of /usr/lib.

#include <libgen.h>
...
char *name = "/usr/lib";
char *base;

base = basename(name); ...
Sample Input and Output Strings for basename()

In the following table, the input string is the value pointed to by path, and the output string is the return value of the basename() function.

Input String

Output String

"/usr/lib"

"lib"

"/usr/"

"usr"

"/"

"/"

"///"

"/"

"//usr//lib//"

"lib"

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

dirname() , the Base Definitions volume of IEEE Std 1003.1-2001, <libgen.h>, the Shell and Utilities volume of IEEE Std 1003.1-2001, basename

CHANGE HISTORY

First released in Issue 4, Version 2.

Issue 5

Moved from X/OPEN UNIX extension to BASE.

Normative text previously in the APPLICATION USAGE section is moved to the DESCRIPTION.

A note indicating that this function need not be reentrant is added to the DESCRIPTION.

Issue 6

In the DESCRIPTION, the note about reentrancy is expanded to cover thread-safety.

End of informative text.


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