Rb_raise problem in C extension


#1

I am using Ruby 1.8.6-26 from the One Click Installer on Windows. I
have a C extension that tries to calloc() memory. If the calloc()
fails I call rb_raise(rb_eNoMemError,“Cannot allocate data”). My
program is getting stuck in this code. Debugging (unfortunately via
print statements) I can see that rb_raise() is going to be called.
After that the exception is never caught by the outermost rescue loop.
The program just stops doing anything (0% cpu) except it keeps
updating a timer in another thread. Are there things I need to know
about rb_raise() and how to use it?


#2

On Apr 22, 2009, at 10:05, removed_email_address@domain.invalid wrote:

I am using Ruby 1.8.6-26 from the One Click Installer on Windows. I
have a C extension that tries to calloc() memory. If the calloc()
fails I call rb_raise(rb_eNoMemError,“Cannot allocate data”). My
program is getting stuck in this code. Debugging (unfortunately via
print statements) I can see that rb_raise() is going to be called.
After that the exception is never caught by the outermost rescue loop.
The program just stops doing anything (0% cpu) except it keeps
updating a timer in another thread. Are there things I need to know
about rb_raise() and how to use it?

If ruby is out of memory how could it allocate more memory to raise an
exception?

Ruby itself allocates a NoMemError at startup to ensure it can raise
one when it runs out of memory. You’ll probably need to do the same.
See gc.c rb_memerror().


#3

On Apr 22, 1:44 pm, Eric H. removed_email_address@domain.invalid wrote:

about rb_raise() and how to use it?

If ruby is out of memory how could it allocate more memory to raise an
exception?

Ruby itself allocates a NoMemError at startup to ensure it can raise
one when it runs out of memory. You’ll probably need to do the same.
See gc.c rb_memerror().

There is plenty of memory available (4-6 gig free). But I’m asking
calloc() for a 1 gb chunk and it can’t find one. Is there a different
exception I should throw in this case? Will the rb_raise() in my
nested C code percolate out to my handler in my nested ruby code? (As
a test for now I’m just changing it to an eException but would
appreciate any feedback you have)


#4

On Wed, 22 Apr 2009 13:44:52 -0500, Eric H. wrote:

If ruby is out of memory how could it allocate more memory to raise an
exception?

Ruby itself allocates a NoMemError at startup to ensure it can raise one
when it runs out of memory. You’ll probably need to do the same. See
gc.c rb_memerror().

Is rb_memerror() exposed for him to call? He could just call that, and
it
would spare him all issues with preallocation.

–Ken


#5

On Apr 22, 2009, at 12:55, removed_email_address@domain.invalid wrote:

updating a timer in another thread. Are there things I need to know
There is plenty of memory available (4-6 gig free). But I’m asking
calloc() for a 1 gb chunk and it can’t find one. Is there a different
exception I should throw in this case? Will the rb_raise() in my
nested C code percolate out to my handler in my nested ruby code? (As
a test for now I’m just changing it to an eException but would
appreciate any feedback you have)

In that case, rb_raise should do what you want, however you may need
to explicitly rescue it:

$ ruby
begin
begin
raise NoMemoryError
rescue
puts “caught with plain rescue”
end
rescue Exception # or NoMemoryError
puts “caught with rescue Exception”
end
^D
caught with rescue Exception

For this reason, you should use RuntimeError or StandardError
(especially for custom error classes) instead of Exception, since
Exception isn’t caught by a plain rescue.


#6

On Apr 23, 2009, at 10:40, Ken B. wrote:

the exception is never caught by the outermost rescue loop. The
Ruby itself allocates a NoMemError at startup to ensure it can
raise one
when it runs out of memory. You’ll probably need to do the same. See
gc.c rb_memerror().

Is rb_memerror() exposed for him to call? He could just call that,
and it
would spare him all issues with preallocation.

yeah, looks like it’s in intern.h.