index() — Search for character

Standards

Format

#define _XOPEN_SOURCE_EXTENDED 1
#include <strings.h>

char *index(const char *string, int c);

General description

The index() function locates the first occurrence of c (converted to an unsigned char) in the string pointed to by string. The character c can be the NULL character (\0); the ending NULL is included in the search.

The string argument to the function must contain a NULL character (\0) marking the end of the string.

The index() function is identical to strchr() — Search for character.

Returned value

If successful, index() returns a pointer to the first occurrence of c (converted to an unsigned character) in the string pointed to by string.

If unsuccessful because c was not found, index() returns a NULL pointer.

There are no errno values defined.

Related information

• strings.h
• memchr() — Search buffer
• rindex() — Search for character
• strchr() — Search for character
• strrchr() — Find last occurrence of character in string
• strspn() — Search string
• strstr() — Locate substring