it is wrong to define a new grpid_t, but not reuse pid_t, because it make getpid(parent) == getppid(child) impossible. Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
as specified here: https://pubs.opengroup.org/onlinepubs/009695399/functions/getppid.html Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>