This often happens when your C code uses memory that it did not allocate, particularly when it reads or writes just a little beyond the end of a memory block. On some platforms or if you are lucky there is unused memory between blocks of allocated memory and you don't see a problem. Other machines may pack allocated memory blocks more tightly and writing off the end of an array corrupts another array, leading to the program crashing. (Or reading off the end of an array may pick up data from the next array, which leads to similar crashes later on.) You may also be reading memory which has never been written to, hence you are using random data, which could corrupt things.
Use a program like valgrind (on Linux, free) or Purify (on various platforms, but pricy) to detect memory misuse in C/C++ code. As long as your code isn't #ifdef'ed for various platforms, you can use valgrind to detect and fix memory misuse on Linux and you will find that overt problems on other platforms will go away. Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of David > Sent: Wednesday, October 13, 2010 6:47 AM > To: r-help@r-project.org > Subject: [R] "Memory not mapped" when using .C,problem in Mac > but not in Linux > > Hello, > > I am aware this may be an obscure problem difficult to advice > about, but > just in case... I am calling a C function from R on an iMac > (almost shining: > bought by my institution this year) and gives a "memory not > mapped" error. > > Nevertheless, exactly the same code runs without problem in a powerful > computer using SuSE Linux, but also on my laptop of 2007, 32 > bits, 2 GB RAM, > running Ubuntu. My supervisor says that he can run my code on > his iMac (a > bit older than mine) without problem. > > I have upgraded to the latest version of R, and I have tried > compiling the C > code with the latest version of gcc (obtained from MacPorts), > but the error > persists. > > Any ideas? > > Thank you very much in advance, > > David > Can you please Cc to me any replies, just in case I may miss > any of them > among the whole amount of emails :-) ? > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
