mq_overview(7) Miscellaneous Information Manual mq_overview(7) mq_overview - POSIX POSIX . System V (msgget(2) msgsnd(2) msgrcv(2) ) . mq_open(3) (mqd_t) . /somename NAME_MAX ( 255) . mq_open(3). mq_send(3) mq_receive(3). mq_close(3) mq_unlink(3). ( ) mq_getattr(3) mq_setattr(3). mq_notify(3). ( open(2)). fork(2) . (mq_flags) . . 0 () sysconf(_SC_MQ_PRIO_MAX) - 1 (). sysconf(_SC_MQ_PRIO_MAX) 32768 POSIX.1 0 31 . POSIX. mq_*() . : mq_close(3) close(2) mq_getattr(3) mq_getsetattr(2) mq_notify(3) mq_notify(2) mq_open(3) mq_open(2) mq_receive(3) mq_timedreceive(2) mq_send(3) mq_timedsend(2) mq_setattr(3) mq_getsetattr(2) mq_timedreceive(3) mq_timedreceive(2) mq_timedsend(3) mq_timedsend(2) mq_unlink(3) mq_unlink(2) POSIX 2.6.6. glibc glibc 2.3.4. POSIX CONFIG_POSIX_MQUEUE. . POSIX : mq_unlink(3) . POSIX cc -lrt librt. /proc POSIX : /proc/sys/fs/mqueue/msg_default ( 3.5) mq_maxmsg mq_open(3) attr NULL. 10. /proc/sys/fs/mqueue/msg_max. mq_maxmsg msg_default msg_max. 2.6.28 mq_maxmsg 10 2.6.28 3.4 msg_max. /proc/sys/fs/mqueue/msg_max . attr->mq_maxmsg mq_open(3). msg_max 10. 1 (10 2.6.28). HARD_MSGMAX. msg_max (CAP_SYS_RESOURCE) HARD_MSGMAX. HARD_MSGMAX : o 2.6.32: 131072 / sizeof(void *) o 2.6.33 3.4: (32768 * sizeof(void *) / 4) o 3.5: 65,536 /proc/sys/fs/mqueue/msgsize_default ( 3.5) mq_msgsize mq_open(3) attr NULL. 8192 (). /proc/sys/fs/mqueue/msgsize_max. msgsize_default msgsize_max mq_msgsize msgsize_max. 2.6.28 mq_msgsize 8192 2.6.28 3.4 msgsize_max. /proc/sys/fs/mqueue/msgsize_max . attr->mq_msgsize mq_open(3). msgsize_max 8192 . 128 (8192 2.6.28). msgsize_max : o 2.6.28 INT_MAX. o 2.6.28 3.4 1,048,576. o 3.5 16,777,216 (HARD_MSGSIZEMAX). msgsize_max (CAP_SYS_RESOURCE) 3.5 HARD_MSGSIZEMAX . /proc/sys/fs/mqueue/queues_max . queues_max 256. queues_max (CAP_SYS_RESOURCE) ( BUGS). RLIMIT_MSGQUEUE getrlimit(2). . ( .) ( ) : # mkdir /dev/mqueue # mount -t mqueue none /dev/mqueue . ( ls(1) rm(1)). : $ cat /dev/mqueue/mymq QSIZE:129 NOTIFY:2 SIGNO:0 NOTIFY_PID:8260 : QSIZE ( BUGS). NOTIFY_PID PID mq_notify(3) . NOTIFY : 0 SIGEV_SIGNAL 1 SIGEV_NONE 2 SIGEV_THREAD. SIGNO SIGEV_SIGNAL. . ( POSIX .) select(2) poll(2) epoll(7). . ( open(2)) mq_open(2). IPC POSIX IPC ipc_namespaces(7). System V (msgget(2) msgsnd(2) msgrcv(2) ) . POSIX System V POSIX ( ) System V. ( 2.6.26) (ACLs) POSIX. 3.5 3.14 1024 (HARD_QUEUESMAX) queues_max . 3.14 3.5.x 3.13.x . () QSIZE ( ) . 3.5 . 4.2 ( ) . mq_notify(3). getrlimit(2) mq_getsetattr(2) poll(2) select(2) mq_close(3) mq_getattr(3) mq_notify(3) mq_open(3) mq_receive(3) mq_send(3) mq_unlink(3) epoll(7) namespaces(7) 3 . . : . 6.18 8 2026 mq_overview(7)