gcc malloc problem with Os X

I am just guessing here, but perhaps you are having trouble because of differences between 64-bit and 32-bit code? Regular 'ole 32 code on a 32 bit OS might just work fine. But you are probably running 32-bit code on a 64 bit OS. You may (keep in mind, this is a guess) be running into limitations of running 32-bit code on a 64-bit machine. Try specifically compiling as 64 bit and also running it on an older Mac.

May be it is a coding error that only shows up on the macintosh. Try this simple test program. In 32 bit mode it should die at about 4GB. In 64 bit mode it should run until it is out of virtual memory. -

#include <stdio.h>
#include <stdlib.h>
main()
{
long n,k,all;
char *m;
long long sum;

sum=0;
all=100000000;
for(n=0;n<100000;++n){
m=(char *)malloc(all);
if(m == NULL){
printf("memory gone\n");
break;
}
for(k=0;k<all;++k)m[k]=k;
sum += all;
fprintf(stderr,"Sum = %lld\n",sum);
}
}

This dum thing puts in a "br" that does not belong and I can not kill.

OK. Here is another guess (inspired by IBM.

What does your VM look like on the Mac compared to the Linux machine? I'm guessing that in order to use that 16 GB, you need to make sure you have that much space free.

If not that, there could be an issue with size of int vs long, etc. int may or may not be 64 bits, depending on your settings. For that, you might have to post some code.

Actually, your virtual mem is how much disk space you have free. If that isn't the cause, you are going to have to post some code. Just saying "it runs fine on Ubuntu" isn't enough. Have you compared the gcc command line settings between the Mac and Linux? Are they identical? Are the libraries you are using identical? Superficially, MacOS X and Linux look alike. But underneath they are quite different. There may be a setting that works on both. I don't know - I'm out of guesses.

One thing that my be your problem is that with most versions of LINUX you can allocate more memory than you actually have and as long as you do not try and access it there is no problem. If you remove the writes to the allocated memory in that test program, it gives inconsistant results on many LINUX systems. So - it is possible that you are allocated extra memory, but not using it and only the Macintosh is having the problem.

You can down load "valgrind" and use it on LINUX to find those kind of problems. It works nicely.