Databases
StackOverflow2013
Postsdbo
POhow to use shared memory to communicate between two processes
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POhow to use shared memory to communicate between two processes
    primarykey
    data
    text
    <p>I am trying to communicate between two processes. I am trying to save data(like name, phone number, address) to shared memory in one process and trying to print that data through other process.</p> <p>process1.c</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;sys/shm.h&gt; #include &lt;sys/stat.h&gt; int main () { int segment_id; char* shared_memory[3]; int segment_size; key_t shm_key; int i=0; const int shared_segment_size = 0x6400; /* Allocate a shared memory segment. */ segment_id = shmget (shm_key, shared_segment_size, IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR); /* Attach the shared memory segment. */ shared_memory[3] = (char*) shmat (segment_id, 0, 0); printf ("shared memory attached at address %p\n", shared_memory); /* Write a string to the shared memory segment. */ sprintf(shared_memory[i], "maddy \n"); sprintf(shared_memory[i+1], "73453916\n"); sprintf(shared_memory[i+2], "america\n"); /*calling the other process*/ system("./process2"); /* Detach the shared memory segment. */ shmdt (shared_memory); /* Deallocate the shared memory segment.*/ shmctl (segment_id, IPC_RMID, 0); return 0; } </code></pre> <hr> <p>process2.c</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;sys/shm.h&gt; #include &lt;sys/stat.h&gt; int main () { int segment_id; char* shared_memory[3]; int segment_size; int i=0; key_t shm_key; const int shared_segment_size = 0x6400; /* Allocate a shared memory segment. */ segment_id = shmget (shm_key, shared_segment_size, S_IRUSR | S_IWUSR); /* Attach the shared memory segment. */ shared_memory[3] = (char*) shmat (segment_id, 0, 0); printf ("shared memory22 attached at address %p\n", shared_memory); printf ("name=%s\n", shared_memory[i]); printf ("%s\n", shared_memory[i+1]); printf ("%s\n", shared_memory[i+2]); /* Detach the shared memory segment. */ shmdt (shared_memory); return 0; } </code></pre> <p>But I am not getting the desired output. the output which i got is:</p> <pre><code>shared memory attached at address 0x7fff0fd2d460 Segmentation fault </code></pre> <p>Anyone can please help me with this. Is this the correct way of initializing <code>shared_memory[3]</code>.</p> <p>Thank you.</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USosgx
    1. USmaddy
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POhow to use shared memory to communicate between two processes
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POhow to use shared memory to communicate between two processes
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POhow to use shared memory to communicate between two processes
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload