NAME
index, rindex – locate character in string
LIBRARY
Standard C Library (libc, -lc)
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 to be part of the string; therefore, if c is ‘\0’, the functions locate the terminating ‘\0’.
The rindex() function is identical to index(), except that 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.