segmentation fault (calloc, free)

Hi,

I've found and fixed a segmentation fault, but was wondering if anyone can explain why it happened in the first place.

At one point i freed some memory that was no longer needed (i'm 99.9 % sure of this). When the next call to calloc happened, bang!

thanks

Perhaps you tried to free the same part of memory twice?

QuantumPete

> When the next call to calloc happened, bang!
You've trashed memory is the most likely cause.

Around each block of memory allocated, the system typically maintains additional information to manage the overall memory pool, and to allow things like free() to work without you also having to specify the size of the memory to be freed.

If you're sloppy with the use of the memory (array oversteps, buffer overruns), you corrupt this hidden (and vital) information, and BANG, your program is dead.