Jim McDonald wrote:
I read your message about this g77 limit in the cygwin mail archives.
I just installed cygwin-1.5.13-1 today and ran into the 160-MByte limit on memory for static variables under g77. I used
g77 -mno-cygwin maxarray.f -o maxarray
to compile
program maxarray real*8 a(240000000) do i=1,240000000 a(i) = i end do print *, a(240000000) stop end
The resulting executable ran to completion. Without -mno-cygwin, the executable returned immediately, with no output or error message. Using -Wl,--stack,8388608 did not help, and actually reduced the memory limit. Setting the registry entry heap_chunk_in_mb to 1024 did not help either, and with that entry still in effect, my array storage has exceeded that limit. I'm running cygwin under Windows 2000 SP4 + latest hotfixes.
If this solution works for you, you may want to post it at cygwin.com or on comp.lang.fortran.
- Jim McDonald Naval Research Lab, Code 6841 (202) 404-6936, fax 767-1280 James.A.McDonald at nrl.dot navy mil
This works now. I can again get 770 Mb of useful array space with 512 Mb of RAM using Windows XP Pro, as I could a couple of years ago by increasing the stack size.
I did try -mno-cygwin before, but without success. Your message prompted me to try again, and now it works. Either I blundered the first time, or there has been some change in my system since then: 1) I reinstalled the old cygwin version for which changing the stack size was at one time, but no longer, an effective fix 2) I cleared the Windows Prefetch directory.
Some comments in the cygwin mail archives suggest that the problem resides in the "cygwin loader" (a modification of gnu ld?). I suppose using -mno-cygwin avoids invoking the cygwin loader, but I am a bit disturbed that the problem did not disappear when I first tried that option. Has anyone else had problems with large fortran arrays when using -mno-cygwin?
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