Open System Services System Calls Reference Manual (G06.25+, H06.03+)

System Functions (k - m) msgctl(2)
NAME
msgctl - Performs message control operations
LIBRARY
G-series native OSS processes: /G/system/sysnn/zossksrl
H-series OSS processes: /G/system/zdllnnn/zosskdll
SYNOPSIS
#include <sys/msg.h>
int msgctl(
int msqid,
int cmd,
struct msqid_ds *buf);
PARAMETERS
msqid Specifies the message queue identifier.
cmd Specifies the type of operation. The possible values for cmd and the operations
they perform are as follows:
IPC_RMID Removes the message queue identifier and deallocates its asso-
ciated msqid_ds structure.
This is a restricted operation. The effective user ID of the calling
process either must have appropriate privileges or must be equal
to the value of the owner’s user ID (msg_perm.uid field) or the
creator’s user ID (msg_perm.cuid field) in the associated
msqid_ds structure.
IPC_SET Sets the message queue identifier by copying selected values in
the structure specified by the buf parameter into corresponding
fields in the msqid_ds structure associated with the message
queue identifier.
This is a restricted operation. The effective user ID of the calling
process must have appropriate privileges or must be equal to the
value of the owner’s user ID (msg_perm.uid field) or the
creator’s user ID (msg_perm.cuid field) in the associated
msqid_ds structure.
Only a process with appropriate privileges can increase the
value of msg_qbytes.
IPC_SETNONFT
Disables fault tolerance for the message queue specified by the
msqid parameter. The default operation of message queues
makes them fault tolerant so that interprocess communication
does not lose data.
This is a restricted operation. The effective user ID of the cal-
ling process must have appropriate privileges or must be equal
to the value of the owner’s user ID (msg_perm.uid field) or the
creator’s user ID (msg_perm.cuid field) in the associated
msqid_ds structure.
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