Gets a message queue identifier.
Standard C Library (libc.a)
int msgget ( Key, MessageFlag)
The msgget subroutine returns the message queue identifier associated with the specified Key parameter.
A message queue identifier, associated message queue, and data structure are created for the value of the Key parameter if one of the following conditions is true:
Upon creation, the data structure associated with the new message queue identifier is initialized as follows:
The msgget subroutine performs the following actions:
Limits on message size and number of messages in the queue can be found in AIX 5L Version 5.1 General Programming Concepts: Writing and Debugging Programs.
|Key||Specifies either the value IPC_PRIVATE or an Interprocess Communication (IPC) key constructed by the ftok (ftok Subroutine) subroutine (or by a similar algorithm).|
|MessageFlag||Constructed by logically ORing one or more of the following values:
Values that begin with S_I are defined in the sys/mode.h file and are a subset of the access permissions that apply to files.
Upon successful completion, the msgget subroutine returns a message queue identifier. Otherwise, a value of -1 is returned and the errno global variable is set to indicate the error.
The msgget subroutine
is unsuccessful if any of the following conditions is true:
|EACCES||A message queue identifier exists for the Key parameter, but operation permission as specified by the low-order 9 bits of the MessageFlag parameter is not granted.|
|ENOENT||A message queue identifier does not exist for the Key parameter and the IPC_CREAT value is not set.|
|ENOSPC||A message queue identifier is to be created, but the system-imposed limit on the maximum number of allowed message queue identifiers system-wide would be exceeded.|
|EEXIST||A message queue identifier exists for the Key parameter, and both IPC_CREAT and IPC_EXCL values are set.|
This subroutine is part of Base Operating System (BOS) Runtime.
The ftok (ftok Subroutine) subroutine, msgctl (msgctl Subroutine) subroutine, msgrcv (msgrcv Subroutine) subroutine, msgsnd (msgsnd Subroutine) subroutine, msgxrcv (msgxrcv Subroutine) subroutine.
The mode.h file.