swab.c\string\src - musl - musl - an implementation of the standard library for Linux-based systems

#include <unistd.h>
void swab(const void *_src, void *_dest, ssize_t n)
{
	const char *src = _src;
	char *dest = _dest;
	for (; n>0; n-=2) {
		dest[0] = src[1];
		dest[1] = src[0];
		dest += 2;
		src += 2;
	}
}