Nicole Willson wrote:
I just noticed that it isn't ignored, but I still don't understand the
purpose.
_RWSTD_TMPBUF_SIZE is #defined to the size of the static temporary
buffer. When get_temporary_buffer() is invoked to request a buffer
whose size in bytes is less than or equal to _RWSTD_TMPBUF_SIZE and
the static buffer is not in use yet the function returns the address
of the buffer to the caller. Otherwise it tries to allocate the
buffer dynamically on the heap. If the allocation fails,
get_temporary_buffer() fails by returning pair(0, 0).
If the check fails, it simply procedes to __rw_allocate.
Since the code I am tracking has sent in a block so large that the code
will not be able to address it all, I would think it would stop here.
Is __rw_allocate supposed to handle this?
__rw_allocate() is just a wrapper around operator new. It throws
an exception on failure. __rw_tmpbuf() catches it and returns
pair(0, 0) instead.
What exactly is the issue you are tracking down? Some compilers
are known to fail the test (with various symptoms) due to a bug.
See, for example
http://bugzilla.cvo.roguewave.com/show_bug.cgi?id=1605
Martin
-----Original Message-----
From: Nicole Willson [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 25, 2006 11:15 AM
To: Stdcxx
Subject: RE: problem in temp_buffer
I'm tracking down an issue with temp_buffer in stdlib/utilities. I'm
confused by a piece of code in source/stdlib/tmpbuf.cpp:
if (nbytes <= _RWSTD_TMPBUF_SIZE) {
if (1 == _RWSTD_THREAD_PREINCREMENT (__rw_buffer_busy, false)) {
*pptr = buffer;
// static buffer used, its usage counter stays non-zero
return _RWSTD_TMPBUF_SIZE / size;
}
// static buffer not used, decrement its usage counter
_RWSTD_THREAD_PREDECREMENT (__rw_buffer_busy, false);
}
_TRY {
*pptr = __rw_allocate (nbytes, 0);
}
_CATCH (...) {
*pptr = 0;
nbytes = 0;
}
return nbytes / size;
What is the purpose of the check against _RWSTD_TMPBUF_SIZE if it is
ignored?
Nicole Willson
Consulting Engineer
Rogue Wave Software, Inc.
A Division of Quovadx
303-545-3210
