Thread View: comp.databases.object
2 messages
2 total messages
Started by Christopher Price
Tue, 19 Sep 1995 20:46
setting C++ object hidden pointers
Author: Christopher Price
Date: Tue, 19 Sep 1995 20:46
Date: Tue, 19 Sep 1995 20:46
25 lines
1582 bytes
1582 bytes
I'm interested in the issue of setting all those vtable related hidden pointers, whilst 'bringing in the sheaves'. Especiallly for virtual bases, there can be a number of compiler-specific schemes, so attempts at redoing what the compiler does will be difficult, requiring a per-os-per-compiler-per-option knowledge table. I have a dec 1993 article from the software- practice and experience journal, entitled 'Making C++ Object Persistent: the Hidden Pointers' by A. Biliris, S. Dar, and N. H. Gehani, all of AT&T Bell labs. Now in that paper they suggest that the new operator can be spilt 1) memory allocation 2) hidden pointer setup 3) call whatever constructor One scheme (which they abandon due to the necessity of rewritting the frequently-used parameterless constructor function), involves placing the object in mem from disk (skipping step 1), step 2 is performed, and a do-nothing parameterless constructor in step 3 is called. My query is whether the new operator can indeed be split up like this. Are they using a non-conforming C++ system? I thought that if you overide the new operator, you don't get any of steps 1 or 2.
Re: setting C++ object hidden pointers
Author: Christopher Price
Date: Tue, 26 Sep 1995 22:16
Date: Tue, 26 Sep 1995 22:16
30 lines
1741 bytes
1741 bytes
On Tue, 19 Sep 1995 20:46:24 GMT, branzcgp@branz.org.nz (Christopher Price) wrote: Just a repost. I'm interested in the issue of setting all those vtable related hidden pointers, whilst 'bringing in the sheaves'. Especiallly for virtual bases, there can be a number of compiler-specific schemes, so attempts at redoing what the compiler does will be difficult, requiring a per-os-per-compiler-per-option knowledge table. I have a dec 1993 article from the software- practice and experience journal, entitled 'Making C++ Object Persistent: the Hidden Pointers' by A. Biliris, S. Dar, and N. H. Gehani, all of AT&T Bell labs. Now in that paper they suggest that the new operator can be spilt 1) memory allocation 2) hidden pointer setup 3) call whatever constructor One scheme (which they abandon due to the necessity of rewritting the frequently-used parameterless constructor function), involves placing the object in mem from disk (skipping step 1), step 2 is performed, and a do-nothing parameterless constructor in step 3 is called. My query is whether the new operator can indeed be split up like this. Are they using a non-conforming C++ system? I thought that if you overide the new operator, you don't get any of steps 1 or 2.
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