mqueue.h(3head) [centos man page]
mqueue.h(3HEAD) Headers mqueue.h(3HEAD) NAME
mqueue.h, mqueue - message queues SYNOPSIS
#include <mqueue.h> DESCRIPTION
The <mqueue.h> header defines the mqd_t type, which is used for message queue descriptors. This will not be an array type. A message queue descriptor may be implemented using a file descriptor, in which case applications can open up to at least OPEN_MAX file and message queues. The <mqueue.h> header defines the sigevent structure (as described in <signal.h>, see signal.h(3HEAD)) and the mq_attr structure, which is used in getting and setting the attributes of a message queue. Attributes are initially set when the message queue is created. A mq_attr structure has the following members: long mq_flags message queue flags long mq_maxmsg maximum number of messages long mq_msgsize maximum message size long mq_curmsgs number of messages currently queued Inclusion of the <mqueue.h> header may make visible symbols defined in the headers <fcntl.h>, <signal.h>, <sys/types.h>, and <time.h>. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
fcntl.h(3HEAD), signal.h(3HEAD), time.h(3HEAD), types.h(3HEAD), attributes(5), standards(5) SunOS 5.10 30 Aug 2002 mqueue.h(3HEAD)
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mq_setattr(3C) Standard C Library Functions mq_setattr(3C) NAME
mq_setattr - set/get message queue attributes SYNOPSIS
#include <mqueue.h> int mq_setattr(mqd_t mqdes, const struct mq_attr *mqstat, struct mq_attr *omqstat); DESCRIPTION
The mq_setattr() function is used to set attributes associated with the open message queue description referenced by the message queue descriptor specified by mqdes. The message queue attributes corresponding to the following members defined in the mq_attr structure are set to the specified values upon successful completion of mq_setattr(): mq_flags The value of this member is either 0 or O_NONBLOCK. The values of mq_maxmsg, mq_msgsize, and mq_curmsgs are ignored by mq_setattr(). If omqstat is non-NULL, mq_setattr() stores, in the location referenced by omqstat, the previous message queue attributes and the current queue status. These values are the same as would be returned by a call to mq_getattr() at that point. RETURN VALUES
Upon successful completion, mq_setattr() returns 0 and the attributes of the message queue will have been changed as specified. Otherwise, the message queue attributes are unchanged, and the function returns -1 and sets errno to indicate the error. ERRORS
The mq_setattr() function will fail if: EBADF The mqdes argument is not a valid message queue descriptor. ENOSYS The mq_setattr() function is not supported by the system. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Committed | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ |Standard |See standards(5). | +-----------------------------+-----------------------------+ SEE ALSO
msgctl(2), msgget(2), msgrcv(2), msgsnd(2), mq_getattr(3C), mq_open(3C), mq_receive(3C), mq_send(3C), mqueue.h(3HEAD), attributes(5), stan- dards(5) NOTES
Solaris 2.6 was the first release to support the Asynchronous Input and Output option. Prior to this release, this function always returned -1 and set errno to ENOSYS. SunOS 5.11 5 Feb 2008 mq_setattr(3C)