Hi, Is the parameters stored on the stack preserved across function calls or volatile in the ABI of intel386 & amd64? I think the answer should be 'volatile' because gcc sometimes did modify them in the callee but couldn't found any description about it in the specifications of Sys V ABI intel386 & amd64. Example: void* get(void* i){ void**p = &i; *p=(void*)0; return p; } gcc yields:(elf32-i386) push ebp mov ebp,esp sub esp,0x10 lea eax,[ebp+0x8] mov DWORD PTR [ebp-0x4],eax mov eax,DWORD PTR [ebp-0x4] mov DWORD PTR [eax],0x0 mov eax,DWORD PTR [ebp-0x4] leave ret Thanks a lot.