On Wed, 18 Jan 2006, LeviPearson wrote:
The readline library expects to be able to call a generator function
with a string and an index and get back a newly-allocated string that it
can use and then free(). To accommodate this, I wrote a C function that
calls a define-external'd scheme function that returns a scheme-object
containing the string. I found that returning a c-string would
sometimes give me some garbage characters as the strings were not always
null-terminated at the right spot.
Hello,
actually I doubt that the termination of strings with a '\0' character is
broken. Maybe the problem is rather related to garbage collection
somehow, if the string is used for a longer time by the readline
library. But nevertheless your approach here looks sensible.
[...] This all seems to work well, but after a bit of use of the
tab-completion functionality, the program segfaults or otherwise dies on
a call to the readline interface.
Well, this is no wonder, because your function gnu-readline is a
foreign-lambda* and not a foreign-safe-lambda*. Callbacks into Scheme are
only safe inside foreign-safe-lambda and friends, otherwise your stack may
unexpectedly be sweeped clean by a minor garbage collection and your C
code won't like that very much.
So just replace the foreign-lambda* by foreign-safe-lambda* in your
readline.scm for every function that may eventually cause a callback intro
Scheme and everything should be fine.
[...]
cu,
Thomas
_______________________________________________
Chicken-users mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/chicken-users
