I find it odd that Larry you would waste memory like that.
See dave_the_m's post. He explains how even the ungreyed box is in previously allocated memory.
| [reply] |
You mentioned it's in previously allocated memory
why??Isn't it created on the fly?
Perl allocates more memory than required for string, that's what xpv_cur/xpv_len is there for
| [reply]
[d/l] |
No, the SV body isn't created at all for SVt_IV scalars.
A SV usually has a head block and a body block (that's in addition to any string buffer, etc). SVt_IV scalars, rather exceptionally, don't have a body. Or rather they have a body, but it's location overlaps the head so that it never needs to be allocated.
5.12, 64 bit ints, 64 bit floats - - -+ <---+
: |
: +04 |
Usual SV head SVt_IV : |
--> +-----------------+ --> +-----------------+ +08 |
| Pointer to body ------+ | Pointer to body ------+
+04 | | | +04 | | +0C
| | | | |
+08 +-----------------+ | +08 +-----------------+ +10
| REFCNT | | | REFCNT |
+0C +-----------+-----+ | +0C +-----------+-----+ +14
| FLAGS | SVt | | | FLAGS | SVt |
+10 +-----------+-----+ | +10 +-----------+-----+ +18
| PV ---> +---------- | | IV/UV |
+14 | | ... | +14 | | +1C
| +---------- | | |
+18 +-----------------+ | +18 +-----------------+ +20
|
Usual SV body |
+-----------------+ <---+
| NV |
| | +04
| |
+-----------------+ +08
| CUR |
| | +0C
| |
+-----------------+ +10
| LEN |
| | +14
| |
+-----------------+ +18
| IV/UV |
| | +1C
| |
+-----------------+ +20
| [reply]
[d/l] |