Hi, Thanks for your quick reply, much appreciated! >> The uncommitted patch at https://gcc.gnu.org/ml/gcc-patches/2016-12/msg01158.html We have looked at this patch. Though we do build the toolchain often, we may not be able to integrate this patch as-is in our gcc-5.3.0 sources due to other dependencies like "__freeres()". Additionally, it would also require to pass '-std=c++11' to our build environment as other dependencies use c++11 keywords. >> Why can't you call the init function on the first call to malloc? For example, >> using a local static variable: We will look into this possibility as well. Thanks! Best Regards, Kaushik -----Original Message----- From: Jonathan Wakely [mailto:jwakely.gcc@xxxxxxxxx] Sent: Thursday, March 23, 2017 5:16 PM To: Kaushik Phatak <Kaushik.Phatak@xxxxxxxx> Cc: gcc-help@xxxxxxxxxxx Subject: Re: Custom malloc fails after gcc-5.x due to changes in eh_alloc.cc On 23 March 2017 at 11:32, Kaushik Phatak wrote: > Hi, > One of our application uses its own custom malloc implementation.