STRSTR(3)

NAME
strstr, strcasestr, strnstr - locate a substring in a string

LIBRARY
libc

SYNOPSIS
#include <string.h>
char *
strstr(const char *big, const char *little);
char *
strcasestr(const char *big, const char *little);
char *
strnstr(const char *big, const char *little, size_t len);
#include <string.h>
#include <xlocale.h>
char *
strcasestr_l(const char *big, const char *little, locale_t loc);

DESCRIPTION
The strstr() function locates the first occurrence of the null-terminated string little in the null-terminated string big.

The strcasestr() function is similar to strstr(), but ignores the case of both strings.

The strcasestr_l() function does the same as strcasestr() but takes an explicit locale rather than using the current locale.

The strnstr() function locates the first occurrence of the null-terminated string little in the string big, where not more than len characters are searched. Characters that appear after a ‘\0’ character are not searched. Since the strnstr() function is a FreeBSD specific API, it should only be used when portability is not a concern.

RETURN VALUES
If little is an empty string, big is returned; if little occurs nowhere in big, NULL is returned; otherwise a pointer to the first character of the first occurrence of little is returned.

EXAMPLES
The following sets the pointer ptr to the "Bar Baz" portion of largestring:

    const char *largestring = "Foo Bar Baz";
    const char *smallstring = "Bar";
    char *ptr;
    ptr = strstr(largestring, smallstring);

The following sets the pointer ptr to NULL, because only the first 4 characters of largestring are searched:

    const char *largestring = "Foo Bar Baz";
    const char *smallstring = "Bar";
    char *ptr;
    ptr = strnstr(largestring, smallstring, 4);

SEE ALSO
memchr(3), memmem(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strtok(3), wcsstr(3)

STANDARDS
The strstr() function conforms to isoC.

HISTORY
The strnstr() function was introduced by FreeBSD 4.5 and is non-standard.