in the string
.IR haystack .
The terminating null bytes (\(aq\\0\(aq) are not compared.
-
+.PP
The
.BR strcasestr ()
function is like
.SH CONFORMING TO
.BR strstr ():
POSIX.1-2001, POSIX.1-2008, C89, C99.
-
+.PP
The
.BR strcasestr ()
function is a nonstandard extension.