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Questions tagged [ipcs]

IPCS is a Linux/Unix command-line utility that provides the status of IPC (Inter-process Communication) facilities.

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How to delete/release a named semaphore from linux command prompt?

I have a code as under.It crashes when accessing the semaphore and I have created "named semaphores" that I am unable to delete from command prompt after the crash. How can I delete them using a command prompt utility? The code is trying to create…
user17569516
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Under what conditions, lrpid of message queue will remain 0 in output of ipcs -qa?

So, I have taken output of ipcs -qa, and I am getting output something like this : T ID KEY MODE OWNER GROUP CREATOR CGROUP CBYTES QNUM QBYTES LSPID LRPID STIME RTIME CTIME q 1111 0X1111 --rw-rw---- oname gname oname gname …
Gaurav Sinha
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shm_open() doesn't create shared memory segment ipcs

I got the following piece of C code which executes successfully: ... fd = shm_open(memory_package_name, O_CREAT | O_RDWR | O_EXCL , S_IRUSR | S_IWUSR); if (fd == -1) { //will fail if file already exists because of flag O_EXCL printf("\n…
Marvin Effing
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Processes accessing a Shared Memory segment returning different values

I'm new to the IPCS concept,i want to achieve that one process creates and initializes a shared memory and then calls another process which attaches to the same shared memory segment and prints the data in the shared memory. However i'm unable to…
arjun gaur
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freeing memory across processes using shmclt() returning an invalid argument error

i am creating several child processes in my programming so i have decided to create an array of shared memory like so: void makeSharedArr(int sharedId, int ** sharedArr, int numArgs) { sharedId = shmget(IPC_PRIVATE, numArgs*sizeof(int), 0666…
lest96
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Delete shared memory with iprm in Linux fails

I'm working with shared memory and I am testing memory reference overflow. I have some problems in my code and I can't delete all memory segments I'm trying like this: ipcs -m ipcrm -m 360448 ipcs -m The memory segment never deletes ------…
Eduardo Wallace
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Which is the INT limit when I create a shared memory (shmop_open) in the KEY? (PHP)

When I created a shared memory segment, I used an Integer for the shared memory key. Now, I need to know the limit in the int number for this key. I know the limit in int32 is 2147483647 and the limit in int64 is 9223372036854775807 If I create a…
Eduardo Wallace
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linux, Apache & ipcs

last night my apache server has crashed with error: (28)No space left on device: AH00023: Couldn't create the ldap-cache mutex after googling where error was I've discovered that was something linked with apache semaphore management. I've kill any…
Stefano Radaelli
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C Unix semaphores: process should wait for 0, but doesn't

have written two simple functions, one for setting a semaphore to an arbitrary value (Reset) and another one to make the process calling it wait for the semaphore to be zero: int R(int semid, int semnum, int val) // reset { union semun arg; …
sowdust
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IPCS message passing related queries

I am dealing with Message Passing IPCS method. I do have few question regarding this: KEY field in ipcs -q shows me 0x00000000 what does this means ? Can i see what messsage is passes using msqid ? If two entries are present (for a particular…
Mayank Jain
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How are ordered the messages insinde an IPC queue

I need to known if that the messages insinde an IPC queue is orderered. In practise I need to know if when a call a msgrvc function I get the first message enetered the queue or the selected message is random. Now, I put this question because when…
enzo1959
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removing shared memories with ipcrm

I'm allocating some shared Memories and Message Queues with specific perm "644". Removing them manually is a hard work so I want to know how can I remove all the rows with that specific perm 644. e.g ------ Shared Memory Segments -------- key …
user2421137
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Duplicate keys using ftok()

I have an existing code in system that uses ftok() to generate key based on the file name and a zero passed to it. The code was working fine on 32 bit but starts complaining randomly when moved to 64 bits. On researching more , I found that this is…
Sachin
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