https://www.gnu.org/software/libc/manual/html_node/Atomic-Types.html#Atomic-Types says - In practice, you can assume that int is atomic. You can also assume that pointer types are atomic; that is very convenient. Both of these assumptions are true on all of the machines that the GNU C Library supports and on all POSIX systems we know of.
My question is whether pointer assignment can be considered atomic on x86_64 architecture for a C program compiled with gcc m64 flag. OS is 64bit Linux and CPU is Intel(R) Xeon(R) CPU D-1548. One thread will be setting a pointer and another thread accessing the pointer. There is only one writer thread and one reader thread. Reader should either be getting the previous value of the pointer or the latest value and no garbage value in between.
If it is not considered atomic, please let me know how can I use the gcc atomic builtins or maybe memory barrier like __sync_synchronize to achieve the same without using locks. Interested only in C solution and not C++. Thanks!