common.go

package ipc

import (
	"math/bits"
)

const (
	// https://code.woboq.org/userspace/glibc/sysdeps/unix/sysv/linux/bits/ipc.h.html
	// Mode bits for `msgget', `semget', and `shmget'.
	IPC_CREAT  = 01000 // Create key if key does not exist.
	IPC_EXCL   = 02000 // Fail if key exists.
	IPC_NOWAIT = 04000 // Return error on wait.

	// Control commands for `msgctl', `semctl', and `shmctl'.
	IPC_RMID     = 0  // Remove identifier.
	IPC_SET      = 1  // Set `ipc_perm' options.
	IPC_STAT     = 2  // Get `ipc_perm' options.
	IPC_INFO     = 3  // See ipcs.
	MSG_STAT     = 11 // See https://man7.org/linux/man-pages/man2/msgctl.2.html, msqid is an index rather than a msg queue id
	MSG_INFO     = 12 // See https://man7.org/linux/man-pages/man2/msgctl.2.html
	MSG_STAT_ANY = 13 // See https://lore.kernel.org/linux-api/20180215162458.10059-4-dave@stgolabs.net/

	// Special key values.
	IPC_PRIVATE = 0 // Private key. NOTE: this value is of type __key_t, i.e., ((__key_t) 0)
)

var msgmax = 8192                // default size, will be overriden during init to match system msgmax
var uintSize = bits.UintSize / 8 // size of a uint, arch dependent

type Msgbuf struct {
	Mtype uint
	Mtext []byte
}

func Msgmax() int {
	return msgmax
}