STRSTR(3) BSD Library Functions Manual STRSTR(3)NAME
strcasestr, strcasestr_l, strnstr, strstr — locate a substring in a
string
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strcasestr(const char *s1, const char *s2);
char *
strnstr(const char *s1, const char *s2, size_t n);
char *
strstr(const char *s1, const char *s2);
#include <string.h>
#include <xlocale.h>
char *
strcasestr_l(const char *s1, const char *s2, locale_t loc);
DESCRIPTION
The strstr() function locates the first occurrence of the null-terminated
string s2 in the null-terminated string s1.
The strcasestr() function is similar to strstr(), but ignores the case of
both strings.
The strnstr() function locates the first occurrence of the null-termi‐
nated string s2 in the string s1, where not more than n 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.
While the strcasestr() function uses the current locale, the
strcasestr_l() function may be passed a locale directly. See xlocale(3)
for more information.
RETURN VALUES
If s2 is an empty string, s1 is returned; if s2 occurs nowhere in s1,
NULL is returned; otherwise a pointer to the first character of the first
occurrence of s2 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 ALSOmemchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3),
strspn(3), strtok(3), wcsstr(3), xlocale(3)STANDARDS
The strstr() function conforms to ISO/IEC 9899:1990 (“ISO C90”).
BSD October 11, 2001 BSD
