Section B.4. IPC Reference: AIX-Linux

B.4. IPC Reference: AIX-Linux

Table B-4. AIX and Linux IPC API Comparison: Semaphores
AIX	LINUX	AIX ERRNO(s)	LINUX ERRNO(s)	Description
`sem_init`	`sem_init`	`EFAULT`	`EINVAL`	Initializes the semaphore object.
		`EINVAL`	`ENOSYS`
		`ENFILE`
		`ENOMEM`
		`ENOSPC`
		`ENOTSUP`
`sem_wait`	`sem_wait`	`EACCES`	Does not set `Errno`. Always returns 0.	Suspends the calling thread until the semaphore pointed to by sem has nonzero count.
		`EAGAIN`
		`(semwait` only)
		`EFAULT`
		`EIDRM`
		`EINTR`
`sem_trywait`	`sem_trywait`	`EINVAL`	`EAGAIN`
		`ENOMEM`
		`ENOTSUP`
`sem_post`	`sem_post`	`EACCES`	`ERANGE`	Unlocks a semaphore.
		`EFAULT`
		`EIDRM`
		`EINVAL`
		`ENOMEM`
		`ENOTSUP`
`sem_getvalue`	`sem_getvalue`	`EACCES`	Does not set errno. Always returns 0.	Gets the value of a semaphore.
		`EFAULT`
		`EINVAL`
		`ENOMEM`
		`ENOTSUP`
`sem_destroy`	`sem_destroy`	`EACCES`	`EBUSY`	Destroys a semaphore object, freeing the resources it might hold.
		`EFAULT`
		`EINVAL`
		`ENOTSUP`
`sem_timedwait`	`sem_timedwait`	`EFAULT`	`EENVAL`	Advanced real-time wait.
		`EINVAL`	`ETIMEDWAIT`
		`ETIMEDWAIT`	`EDEADLK`
		`EDEADLK`	`ENTR`
		`ENtr`
`sem_unlink`	`sem_unlink`	`EACCES`	`EACCES`	Removes a named semaphore.
		`EFAULT`	`ENAMETOLONG`
		`ENAMETOOLONG`	`ENOENT`
		`ENOENT`
		`ENOTSUP`
`sem_close`	`sem_close`	`EFAULT`	`EINVAL`	Closes a named semaphore.
		`EINVAL`
		`ENOMEM`
		`ENOTSUP`
`sem_open`	`sem_open`	`EACCES`	`EACCES`	Opens a named semaphore.
		`EEXIST`	`EEXIST`
		`EFAULT`	`EINTR`
		`EINVAL`	`EENVAL`
		`EMFILE`	`EMFILE`
		`ENAMETOOLONG`	`ENAMETOOLONG`
		`ENOMEM`	`ENFILE`
		`ENOTSUP`	`ENOENT`
		`ENOSPC`	`ENOSPC`

Table B-5. AIX and Linux IPC API Comparison: Message Queues
AIX -> Linux	AIX ERRNO(s)	Linux ERRNO(s)	Description
`mq_close`	`EBADF`	`EBADF`	Closes a message queue.
	`ENOMEM`	`EBUSY`
	`ENOTSUP`
`mq_open`	`EACCES`	`EACCES`	Opens a message queue.
	`EEXIST`	`EEXIST`
	`EFAULT`	`EINTR`
	`EINVAL`	`EINVAL`
	`ENOMEM`	`EMFILE`
	`ENOSPC`	`ENOSPC`,
	`ENOTSUP`	`ENOENT`
	`ENOENT`	`ENFILE`
	`ENFILE`	`ENAMETOOLONG`
	`ENAMETOOLONG`
`mq_notify`	`EBADF`	`EBADF`	Notifies a process that a message is available.
	`EBUSY`	`EBUSY`
	`EFAULT`
	`ENOMEM`
	`ENOTSUP`
	`EINVAL`
`mq_getattr`	`EBADF`	`EBADF`	Gets message queue attributes.
	`EFAULT`
	`ENOMEM`
	`EINVAL`
	`ENOTSUP`
`mq_unlink`	`EACCES`	`EACCES`	Removes a message queue.
	`EFAULT`	`ENOENT`
	`EINVAL`	`ENAMETOOLONG`
	`ENAMETOOLONG`,
	`ENOTSUP`
`mq_send`	`EAGAIN`	`EAGAIN`	Sends a message to the message queue
	`EFAULT`	`EBADF`
	`EBADF`	`EINTR`
	`EIDRM`	`EINVAL`
	`EINTR`	`EMSGSIZE`
	`EINVAL`
	`EMSGSIZE`
	`ENOMEM`
	`ENOTSUP`
`mq_setattr`	`EBADF`	`EBADF`	Sets message queue attributes
	`EFAULT`
	`EINVAL`
	`ENOMEM`
	`ENOTSUP`
`mq_send mq_timedsend`,	`EAGAIN`	`EAGAIN`	Sends a message to a message queue (REALTIME)
	`EBADF`	`EBADF`
	`EFAULT`	`EINTR`
	`EIDRM`	`EINVAL`
	`EINTR`	`EMSGSIZE`
	`EINVAL`	`ETIMEDOUT`
	`EMSGSIZE`
	`ENOTSUP`
	`ETIMEDOUT`
`mq_receive`	`EAGAIN`	`EAGAIN`	Receives a message from a message queue
	`EBADF`	`EBADF`
	`EFAULT`	`EINVAL`
	`EIDRM`	`EMSGSIZE`
	`EINTR`	`EINTR`
	`EINVAL`	`EINVAL`
	`EMSGSIZE`	`ETIMEOUT`
	`ENOMEM`
	`ENOTSUP`
`msgctl`	`EACCES`	`EACCES`	Provides message control operations
	`EPERM`	`EPERM`
	`EFAULT`	`EDIRM`
	`EINVAL`	`EFAULT`
		`EINVAL`
`msgget`	`EACCES`	`ENOMEM`	Gets a message queue identifier.
	`ENOENT`	`EACCES`
	`EEXIST`	`ENOENT`
	`ENOSPC`	`EEXIST`
		`ENOSPC`
`msgrcv`	`E2BIG`	`E2BIG`	Reads a message from a queue.
	`EACCES`	`EACCES`
	`ENOMSG`	`ENOMSG`
	`EFAULT`	`EFAULT`
	`EINTR`	`EINTR`
	`EIDRM`	`EIDRM`
	`EINVAL`	`EINVAL`

Table B-6. AIX and Linux POSIX Threads Comparison: APIs Shown to Have Differences
API	Differences
`pthread_attr_getschedparam`	In AIX, the API takes two parameters:
`pthread_attr_setschedparm`	`pthread_attr_t*`
	`struct sched_param*`
	In Linux, the API takes three parameters:
	`pthread_t`
	`int (policy)`
	`struct sched_param*`
`pthread_attr_init`	Creates a new thread attribute with default values with the following exceptions.
	AIX:
	Contention scope = PTHREAD_SCOPE_PROCESS
	`Sched param.sched_prio = 1`
	Linux:
	Contention scope = PTHREAD_SCOPE_SYSTEM
	`Sched param.sched_priority = 0`
`pthread_mutex_lock pthread_mutex_trylock pthread_mutex_unlockj`	Lock mechanism between AIX and Linux is not compatible. The conditions for deadlocking differ, and the attribute values differ.
	AIX: Possible attribute values are as follows:
	`PTHREAD_MUTEX_NORMAL`
	`PTHREAD_MUTEX_ERRORCHECKING`
	`PTHREAD_MUTEX_RECURSIVE`
	`PTHREAD_MUTEX_DEFAULT`
	Linux: Possible attribute values are as follows:
	`#ifdef __USE_GNU`
	`PTHREAD_MUTEX_INITIALIZER`
	`PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP`
	`PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP`
	`#ifdef __USE_UNIX98`
	`PTHREAD_MUTEX_NORMAL`
	`PTHREAD_MUTEX_ERRORCHECKING`
	`PTHREAD_MUTEX_RECURSIVE`
	`PTHREAD_MUTEX_DEFAULT`
`pthread_mutexattr_gettype`	Gets or sets a mutex type to the following values.
`pthread_mutexattr_settype`	AIX: Possible attribute values are as follows:
	`PTHREAD_MUTEX_NORMAL`
	`PTHREAD_MUTEX_ERRORCHECKING`
	`PTHREAD_MUTEX_RECURSIVE`
	`PTHREAD_MUTEX_DEFAULT`
	Linux: Possible attribute values are as follows:
	`#ifdef __USE_GNU`
	`PTHREAD_MUTEX_INITIALIZER`
	`PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP`
	`PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP`

	`#ifdef __USE_UNIX98`
	`PTHREAD_MUTEX_NORMAL`
	`PTHREAD_MUTEX_ERRORCHECKING`
	`PTHREAD_MUTEX_RECURSIVE`
	`PTHREAD_MUTEX_DEFAULT`

B.4. IPC Reference: AIX-Linux

Table B-4. AIX and Linux IPC API Comparison: Semaphores

Table B-5. AIX and Linux IPC API Comparison: Message Queues

Table B-6. AIX and Linux POSIX Threads Comparison: APIs Shown to Have Differences