strnstr(3) locate a substring in a string


Lb libbsd


In bsd/string.h Ft char * Fn strnstr const char *big const char *little size_t len


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


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


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);