### 5.30 `strncmp`—character string compare

Synopsis

         #include <string.h>
         int strncmp(const char *a, const char * b, size_t length);

Description
`strncmp` compares up to length characters from the string at a to the string at b.

Returns
If `*`a sorts lexicographically after `*`b, `strncmp` returns a number greater than zero. If the two strings are equivalent, `strncmp` returns zero. If `*`a sorts lexicographically before `*`b, `strncmp` returns a number less than zero.

Portability
`strncmp` is ANSI C.

`strncmp` requires no supporting OS subroutines.