On Mon, Mar 12, 2018 at 12:16 PM, Richard Klingler <rich...@klingler.net> wrote:
> ZEND_FUNCTION(readmydevice)
> {
> zend_long n;
> zval *z;
> size_t len;
> char *p;
> long r;
>
> if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "lzl", &n,
> &z, &len) == FAILURE) {
> return;
> }
>
> p = (char *) emalloc(len + 1);
> memset(p,0,len+1);
>
> r = myread(n, p, len);
> printf("Read %d bytes from device %d up to %d bytes\n", mycount,
> n, len);
> p[ibcnt] = '\0';
> ZVAL_STRINGL(z, p, mycount);
> printf("Returned %s\n", p);
> efree(p);
> RETURN_LONG(r);
> }
>
>
> Any ideas why ZVAL_STRINGL is not doing anything?
> Or did I miss something?
>
Well, ZVAL_STRINGL is probably doing something, but there are two
reasons there's no way to be certain:
1. What is 'mycount' and where does it come from / how is it set? If
it's zero, then you'll be saving a zero length string. In any case, it
doesn't seem to have any relationship to the data read into `p`. I'm
guessing you wanted to use `r` rather than `mycount` both here and in
your debug message.
2. I'm inferring that you want argument 2 to your function to be a
pass-by-ref argument. Are you specifying any arg_info in the function
entry list? (where you have your PHP_FE macro -- or perhaps ZEND_FE
macro, since you seem to be using those versions). In order to pass
by ref, you need that structure to specify that the argument is
by-ref. This *might* have worked without it in PHP 5, but only by
accident and would have probably failed in hard-to-diagnose ways.
2a. Also, when using by-ref args, you need to destruct any previously
held value. In this case, with a zval_dtor(z); prior to the
ZVAL_STRINGL() macro.
-Sara
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