Memory allocation overflow in c program Home › Forums › C Programming › Memory allocation overflow in c program This topic contains 0 replies, has 1 voice, and was last updated by Carmelo38I 8 years, 8 months ago. Author Posts May 19, 2009 at 2:51 pm #2199 Carmelo38IMember In a large system I try to allocate about 1GB of memory on a 4GB system and it blows up (returns a NULL pointer in C), Now I tried to allocate 1GB from a small test program and it also returns null. Also, I have implemented the /LARGEADDRESSLIMIT switch on the Linker, to be able to address more than 2GB RAM. But the system does not want to allocate 1GB, when the available memory is 1.8GB according to the Task Manager!! ex: BYTE *bb=(BYTE*) calloc(0.9, 0x40000000); where BYTE is unsigned char I can only allocate about 400MB, otherwise I get NULL How much memory I can allocate from a C program ? It looks like there is something I don’t quite understand about the x86 memory model. Author Posts You must be logged in to reply to this topic.