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Shared memory in Linux allows multiple processes to access a common memory segment, enabling efficient inter-process communication. Below are two common methods to implement shared memory in C.
1. Using mmap
The mmap function is a modern and flexible way to create shared memory.
Steps:
Use mmap to allocate a shared memory buffer.
Set the MAP_SHARED flag to allow sharing between processes.
Use fork() to create child processes that can access the shared memory.
Example Code:
#include <stdio.h>#include <stdlib.h>#include <sys/mman.h>#include <string.h>#include <unistd.h>void* create_shared_memory(size_t size) {int protection = PROT_READ | PROT_WRITE;int visibility = MAP_SHARED | MAP_ANONYMOUS;return mmap(NULL, size, protection, visibility, -1, 0);}int main() {char parent_message[] = "Hello from parent";char child_message[] = "Hello from child";void* shmem = create_shared_memory(128);memcpy(shmem, parent_message, sizeof(parent_message));if (fork() == 0) { // Child processprintf("Child read: %s\n", (char*)shmem);memcpy(shmem, child_message, sizeof(child_message));printf("Child wrote: %s\n", (char*)shmem);} else { // Parent processsleep(1); // Wait for child to writeprintf("Parent read: %s\n", (char*)shmem);}return 0;}Copied!✕Copy Shared Memory in Linux: A Comprehensive Guide - linuxvox.com
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Code sample
char parent_message[] = "hello";char child_message[] = "goodbye";void* shmem = create_shared_memory(128);memcpy(shmem, parent_message, sizeof(parent_message));int pid = fork();...Using Shared Memory in Linux - DEV Community
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GitHub - jandriea/simple-shmem: Simple Shared Memory Example
This repository provides a simple example of how to use shared memory for interprocess communication in a Unix-like environment.
shm_overview (7) — Linux manual page - man7.org
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