If you don't want to learn a new utility, something I like to do in situations like this, is rather than using malloc/realloc straight I use the macros below. Actually, I just used this on monday to find why I was getting the error you got. Turns out it was the pointer had been moved away from the initial allocated space and into the middle of the array that I had allocated, and I didn't take that into account before I called free(). #ifdef DEBUG_MEMORY #include <stdio.h> #define malloc_info( Y, X ) \ (Y) = malloc(X); fprintf(stderr, "Memory allocated at position 0x%08X @ %s :: %d\n", (Y), __FILE__, __LINE__); #endif #define realloc_info( X, Y, X ) \ (X) = realloc(Y, X); fprintf(stderr, "Memory reallocation at position 0x%08X (now at position 0x%08X) @ %s :: %d\n", (Y), (X), __FILE__, __LINE__); #endif #define free_info( X ) \ fprintf(stderr, "Memory freed at position 0x%08X @ %s :: %d\n", (X), __FILE__, __LINE__); free(X); #endif #else #define malloc_info( Y, X ) \ (Y) = malloc(X); #endif #define realloc_info( X, Y, X ) \ (X) = realloc(Y, X); #endif #define free_info( X ) \ free(X); #endif #endif However, in larger programs, this could be quite a nightmare with lots of output, or if you cannot use console IO on your program. A friend of mine strongly recommends that valgrind environment, so I suspect it is strongly worth looking into. -Jim On 3/8/06, Digvijoy Chatterjee <digvijoy_chatterjee@xxxxxxxxxxx> wrote: > > I had a similar problem once ,and valgrind is worth a try , if Mike > hasn't done it already. > > -- > Thanks and Regards > Digvijoy Chatterjee > > > On Tue, 2006-03-07 at 08:55 -0800, Brian Budge wrote: > > Hi Mike - > > > > Memory problems can definitely be strange. This is because it can be > > the case that your mistake and the error can seem to have very little > > in common either spatially and/or temporally. > > > > I suggest you look for any cases where you might possibly be > > overrunning an array or accessing memory outide of a structure, etc... > > What happens is that malloc returns a chunk of memory with special > > data at the front of it, so that when free is called, free can delete > > the appropriate memory. > > > > It seems like what may have happened is that this special chunk has > > been trampled, so it doesn't agree with what glibc thinks it should > > be. > > > > Good luck! Memory is hard to debug :( > > > > Brian > > > > On 3/7/06, Mike McWilliam <pilot.mm@xxxxxxxxx> wrote: > > > Hello There > > > > > > I have some problems with some C++ code and the g++ compiler. > > > I have two Suse Linux machines running on two different computers let > > > me give you the info for each one > > > > > > Machine One > > > -------------------------- > > > OS: SuSE 10.0 > > > Arcitecture: AMD Athlon 64 2200 > > > RAM: 512 MB > > > Motherboard: Asus K8E SE > > > G++ Version: 4.0.2 > > > GNU GLibC: 2.3.5-40 > > > > > > Machine Two > > > -------------------------- > > > OS: SuSE 10.0 > > > Arcitecture: Intel Pentium IV 2.4 GHz > > > RAM: 512 MB > > > Motherboard: ??? > > > G++ Version: 4.0.2 > > > GNU GLibC: 2.3.5-40 > > > > > > Identical SW platform, however one uses the 64 bt > > > architecture. So some HW differences. Now the problem was that the > > > Code was developed on Machine one and ran with no problems. However > > > when it is ran on machine Two I get the following error very early in > > > the code: > > > > > > *** glibc detected *** free(): invalid next size (normal): 0x080da638 *** > > > Aborted > > > > > > I can't seem to find the offending pointer 0x080da638. Memory > > > leaks and array out of bound errors should not be there since it > > > worked on Machine One. I've combed through my code several times to > > > find something. Yet I get nothing. Could you help me out on where I > > > can go to solve this problem. I would like code from machine one to > > > work on machine two for obvious reasons. Thanks for any help you have > > > to offer. > > > > > > Mike > > > > > > > **************** CAUTION - Disclaimer ***************** > This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. > ***INFOSYS******** End of Disclaimer ********INFOSYS*** >
