eval_pv("$string = \"This is a string\"; print(\"$string\\n\");");

##</code><code>##

static void call_some_perl_sub(const char* s) {
    dSP;
    ENTER;
    SAVETMPS;
    PUSHMARK(SP);
    XPUSHs(sv_2mortal(newSVpv(s, strlen(s))));
    PUTBACK;
    call_pv("some_perl_sub", G_DISCARD);
    FREETMPS;
    LEAVE;
}