On Thursday, December 23, 2010 at 11:00:26 (-0800) Alan W. Irwin writes: > Maurice, do you know the origins of the free_mem macro in > include/plplotP.h? That does deal with the NULL pointer case for > frees, but it also sets the pointer to NULL after every free so I > think this macro was meant to be used to guard against double frees of > the same memory. OTOH, another interpretation is the author of that > macro had run into a badly implemented free implementation that didn't > deal properly with a NULL pointer.
I wrote free_mem as syntactic sugar. I don't think badly implemented free()'s were part of the equation but I can't be sure. So the "sugar" is as follows: - guard against a double free - related: since double free's become a no-op, if control flow becomes thorny you can put a free_mem in anywhere to be sure memory gets freed - the pointer is zeroed out since it bugged me to no end to have bogus pointers around. Especially when debugging. -- Maurice LeBrun ------------------------------------------------------------------------------ Learn how Oracle Real Application Clusters (RAC) One Node allows customers to consolidate database storage, standardize their database environment, and, should the need arise, upgrade to a full multi-node Oracle RAC database without downtime or disruption http://p.sf.net/sfu/oracle-sfdevnl _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
