NAME
index, rindex
— locate character in
string
LIBRARY
library “libc”
SYNOPSIS
#include
<strings.h>
char *
index(const
char *s, int
c);
char *
rindex(const
char *s, int
c);
DESCRIPTION
The
index()
function locates the first occurrence of c (converted
to a char) in the string pointed to by
s. The terminating null character is considered part
of the string; therefore if c is
‘\0’, the functions locate the
terminating ‘\0’.
The
rindex()
function is identical to index(), except it locates
the last occurrence of c.
RETURN VALUES
The functions index() and
rindex() return a pointer to the located character,
or NULL if the character does not appear in the
string.
SEE ALSO
memchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3), strtok(3)
HISTORY
The index() and
rindex() functions appeared in
Version 6 AT&T UNIX. Their prototypes
existed previously in
<string.h> before they were
moved to <strings.h> for
IEEE Std 1003.1-2001 (“POSIX.1”)
compliance. The functions are not specified by IEEE Std
1003.1-2008 (“POSIX.1”).