Finita la conversione dei listati in file separati. Passato anche alla nuova

[gapil.git] / listati / SharedMem.c

diff --git a/listati/SharedMem.c b/listati/SharedMem.c
new file mode 100644 (file)
index 0000000..9f5b438
--- /dev/null
+++ b/listati/SharedMem.c
@@ -0,0 +1,51 @@
+/* Function ShmCreate  Create a SysV shared memory segment */
+void * ShmCreate(key_t ipc_key, int shm_size, int perm, int fill) 
+{
+    void * shm_ptr;
+    int shm_id;                       /* ID of the IPC shared memory segment */
+    shm_id = shmget(ipc_key, shm_size, IPC_CREAT|perm);        /* get shm ID */
+    if (shm_id < 0) { 
+        return NULL;
+    }
+    shm_ptr = shmat(shm_id, NULL, 0);                  /* map it into memory */
+    if (shm_ptr < 0) {
+        return NULL;
+    }
+    memset((void *)shm_ptr, fill, shm_size);                 /* fill segment */
+    return shm_ptr;
+}
+/* Function ShmFind: Find a SysV shared memory segment  */
+void * ShmFind(key_t ipc_key, int shm_size) 
+{
+    void * shm_ptr;
+    int shm_id;                      /* ID of the SysV shared memory segment */
+    shm_id = shmget(ipc_key, shm_size, 0);          /* find shared memory ID */
+    if (shm_id < 0) {
+        return NULL;
+    }
+    shm_ptr = shmat(shm_id, NULL, 0);                  /* map it into memory */
+    if (shm_ptr < 0) {
+        return NULL;
+    }
+    return shm_ptr;
+}
+/* Function ShmRemove: Schedule removal for a SysV shared memory segment  */
+int ShmRemove(key_t ipc_key, void * shm_ptr) 
+{
+    int shm_id;                      /* ID of the SysV shared memory segment */
+    /* first detach segment */
+    if (shmdt(shm_ptr) < 0) {
+        return -1;
+    }
+    /* schedule segment removal */
+    shm_id = shmget(ipc_key, 0, 0);                 /* find shared memory ID */
+    if (shm_id < 0) {
+        if (errno == EIDRM) return 0;
+        return -1;
+    }
+    if (shmctl(shm_id, IPC_RMID, NULL) < 0) {             /* ask for removal */
+        if (errno == EIDRM) return 0;
+        return -1;
+    }
+    return 0;
+}