index(3C) Standard C Library Functions index(3C)
NAME
index, rindex - string operations
SYNOPSIS
#include <strings.h>
char *index(const char *s, int c);
char *rindex(const char *s, int c);
DESCRIPTION
The index() and rindex() functions operate on null-terminated strings.
The index() function returns a pointer to the first occurrence of character c in string s.
The rindex() function returns a pointer to the last occurrence of character c in string s.
Both index() and rindex() return a null pointer if c does not occur in the string. The null character terminating a string is considered
to be part of the string.
USAGE
On most modern computer systems, you can not use a null pointer to indicate a null string. A null pointer is an error and results in an
abort of the program. If you wish to indicate a null string, you must use a pointer that points to an explicit null string. On some
machines and with some implementations of the C programming language, a null pointer, if dereferenced, would yield a null string. Though
often used, this practice is not always portable. Programmers using a null pointer to represent an empty string should be aware of this
portability issue. Even on machines where dereferencing a null pointer does not cause an abort of the program, it does not necessarily
yield a null string.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
|ATTRIBUTE TYPE |ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO
bstring(3C), malloc(3C), string(3C), attributes(5), standards(5)
SunOS 5.11 24 Jul 2002 index(3C)