Shared Memory settings

Shared Memory settings recently used the shmget function, and found that the returned value is-1, and the perror result is Invalid argument www.2cto.com. It turned out that the shared memory value was too large, after Ubuntu is installed, the maximum shared memory size is 32 MB by default. There are two ways to set the shared memory: 1. permanently set www.2cto.com a) at/etc/sysctl. add a kernel in the conf file. shmmax = 0x40000000 (set the shared memory to 1 GB) B) Restart system 2. temporary settings a) modify the file/proc/sys/kernel/shmmax and change the value to 1073741824 (the system will expire after restart)