macOS custom new and delete functions

hi

i am in the process of moving all of my projects from visual studio to xcode and am having difficulty with my memory manager

i have a fixed static block of data that i allocate from

when i launch my program it seems that some external functions are calling my new and delete functions before my program starts . this is causing problems for me because this is happening before my static data is initialised

so basically before my program kick in - some external functions are allocating from my data - then my data is initialised - trashing the previous allocations

i understand that replacing new and delete causes external libraries to use your versions ... but i didnt expect them to do this before my data is even initialised

does anyone know a way around this?

thanks