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Questions tagged [sysv]

For Unix-related questions specific to System V IPC, System V init, SVID, etc.

System V is a branch of commercal Unix operating systems, with SVR4 (System V Release 4) being the most succesful and most widely ported version. Modern System V systems include Oracle Solaris, IBM AIX, HP-UX, and others.

System V IPC primitives (message queue, semaphore, shared memory) had been standardized in POSIX and Single Unix Specification.

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System V Message Queue - Timed receive

Im using System V Message Queue, which does not have a "timed receive" function, like POSIX MQ. But now i need it (this timed receive func.). One can ask: "so why dont you use POSIX instead of Sys V?". Because in my benchmarks SysV MQ was +- 20%…
Leonardo Alt
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Is there any possible way to change a memory location to a shared memory in C?

In c you can do shmid = shmget(SHMEM_KEY, sizeof(int*) * n , SHEMEM_MODE | IPC_CREAT); int* shmem = shmat(shmid, NULL, 0); to assign first given free memory space as a shared memory. Is there any way to assigne current memory space as a shared…
Anatoli
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Node.JS and System V Queues / sysv

I've files written in PHP that are using SYSV functions of Linux Systems. The functions that are used in the code being: msg_send, msg_receive and msg_get_queue. My team wants to have the same functionality written in Node.JS. The closest I was at:…
Sanket Tarun Shah
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I have a SysV init script on Fedora 18. How can I make it start after the network is ready?

I have a SysV init script on Fedora 18. Fedora 18 uses systemd (and apparently, there is no way to switch back to SysV). My script requires the network to be ready. Currently, at the time the script runs, the network is not ready. How can I make…
Matt Fichman
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Correctly removing SYS V semaphore used by several processes

I've got a project in which I have to use SYS V semaphores. I've got several processes which share a semaphore (using the same key) and initialize it with this code: bool semaphore_init(semaphore_id_t* sem, int sem_value, key_t key) { /* Try to…
Przemysław Lenart
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install from yocto recipe not able to create init.d folder

In yocto tpm2 recipe the following recipe is not workin fine: install -d "${D}${sysconfdir}/init.d" It's not able to create a folder named init.d. If I change folder name to init_d it is able to create the folder. It appears strange to me becuase…
Neeraj Usadadiya
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Semaphore synchronization on value 0

Using SysV semaphores in a UNIX OS it is possible to implement an algorithm in which a process waits until the value of a semaphore reaches the value 0 (see man semop for details). Now, everybody seems to say that it is better to use other…
Raffo
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how does systemd replace populate-volatiles.sh?

In sysvinit I would have an initscript, populate-volatiles.sh, that reads a volatiles file and creates the volatiles. What performs that function in systemd? Is there a systemd unit that does this? What is it and how do I configure it?
bef.tgz
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I kill process "A" in XV6 , what happens to child processes of "A"

On a normal day , when a process is killed , all its child processes must be attached to 'init' process (Great Grand-Daddy of all processes). Strangely , the XV6 doesn't seem to do so. Below is the code of 'kill' function in proc.c file in XV6 int…
Daksh
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Using shared memory to implement server locally

Shared memory is (possibly) the fastest IPC method available. Is there any well recognized design pattern for implementing a local client/server communication via shared memory? More specifically, a request/response cycle. The scenario is as…
Daniel Lovasko
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Yocto: INITSCRIPT_PARAMS not works as expected

I'm using yocto Krogoth(2.1) and this not works in my startup_1.0.bb: INITSCRIPT_PARAMS = "start 98 S ." startup.sh was copied into /etc/init.d but not linked to /etc/rcS.d/S98startup.sh after bitbake core-image-minimal I googled solutions and even…
Keelung
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Firebird 2.5 Database Server on FreeBSD 11.2

I install a Firebird database server (ver. 2.5) according to the instructions on https://www.howtoforge.com/the-perfect-database-server-firebird-2.5-and-freebsd-8.1 and I get this message "Please do not build firebird as 'root' because this may…
Janush Kvasigroh
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How to implement process-wise mutexes and condition variables

I have two processes running. One is the mainserver and the other is proxy server. They both communicate through a shared memory. Proxy server writes name of the file and mainserver reads it. Then main server writes the content of that file to be…
cranberry
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Why `systemctl list-unit-files` command output does not contain logstash

I Installed ELK (Elasticsearch, Logstash and Kibana) with YUM onto our centos based system and set them as start at boot time. Then When I tried command systemctl list-unit-files, the output only contains Kibana and Elasticsearch without Logstash at…
Rui
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CentOS IPC msg queue filling up with messages from PHP application

I have a long-running PHP application that spawns multiple child processes to run tasks on a CentOS VM, and it uses the SysV IPC message queue (via msg_get_queue(), etc) for sending events to the parent process. The problem is that even though the…
shaneiseminger
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