C garbage collection -crazy idea

[onkar]

This idea might be vey crazy. But I hope to get answers to this .. from
comp.lang.c

If a compiler is designed such that it automatically adds a free()
matching every malloc()
then is it not a garbage collection (in the first place , garbage will
not be generated !! ) . Is it
possible to have a compiler with such feature. Or if Its not a good
idea (or may be this is an idiotic idea) please tell me why is it so ??

 

[Barry]

This idea might be vey crazy. But I hope to get answers to this .. from
comp.lang.c

If a compiler is designed such that it automatically adds a free()
matching every malloc()
then is it not a garbage collection (in the first place , garbage will
not be generated !! ) . Is it
possible to have a compiler with such feature. Or if Its not a good
idea (or may be this is an idiotic idea) please tell me why is it so ??

The first problem that comes to mind is how would a compiler possibly
know where or when to add the free().

 

[Malcolm]

This idea might be vey crazy. But I hope to get answers to this .. from
comp.lang.c

If a compiler is designed such that it automatically adds a free()
matching every malloc()
then is it not a garbage collection (in the first place , garbage will
not be generated !! ) . Is it
possible to have a compiler with such feature. Or if Its not a good
idea (or may be this is an idiotic idea) please tell me why is it so ??

Garbage collection itself is a good idea. One way of doing it would be to
match mallocs() with free and forbid returning alocated memory from a
function. However this would disallow many useful data structures.
The way most languages do it is to tag areas of memory, and free them when
they finally go out of scope. The disadvantage with this is that the garbage
collection becomes non-trivial, and fairly though not excessively processor
intensive.

Jacob Navia has added garbage collection to C. You might want to check out
his lcc-win compiler (Goggle for his name and lcc-win).

Whether it is a good idea to extend the C language this way is a moot point.
It changes one of the most fundamental characteristics of the language,
which is that every line of C matches to a few simple assembly instructions.
OK some pedant will post a 1024-line of C which is incredibly hard to
hand-compile. But generally the rule holds.

 

[Richard Heathfield]

Malcolm said:

Jacob Navia has added garbage collection to C.

C does not appear to have noticed.