Programma per scrivere su una shared memory.

[gapil.git] / sources / WriteShm.c

diff --git a/sources/WriteShm.c b/sources/WriteShm.c
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+/* WriteShm.c
+ * 
+ * Copyright (C) 2002 Simone Piccardi
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/*****************************************************************************
+ *
+ * File WriteShm.c: 
+ *
+ * An example of POSIX shared memory use: wwrite some content to a
+ * shared memory segment
+ *
+ * Author: S. Piccardi Jan. 2003
+ *
+ * $Id: WriteShm.c,v 1.1 2003/02/03 18:07:38 piccardi Exp $
+ *
+ *****************************************************************************/
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>        /* directory */
+#include <stdlib.h>        /* C standard library */
+#include <unistd.h>
+#include <stdio.h>
+
+#include "Gapil.h"
+#include "macros.h"
+
+/* Help printing routine */
+void usage(void);
+
+int main(int argc, char *argv[]) 
+{
+    int i;
+    int size = 4096;
+    char * file_name = NULL;
+    int fd = 0;
+    int mutex;
+    char * mutex_file;
+    void * shm_ptr;
+    /*
+     * Input section: decode command line parameters 
+     * Use getopt function
+     */
+    opterr = 0;         /* don't want writing to stderr */
+    while ( (i = getopt(argc, argv, "hs:f:")) != -1) {
+       switch (i) {
+       /* 
+        * Handling options 
+        */ 
+       case 's':                                     /* set pause (in sec.) */
+           size = strtol(optarg, NULL, 10);
+           break;
+       case 'f':                                     /* set pause (in sec.) */
+           file_name = optarg;
+           break;
+       case 'h':                                             /* help option */
+           printf("Wrong -h option use\n");
+           usage();
+           return -1;
+           break;
+       case '?':                                    /* unrecognized options */
+           printf("Unrecognized options -%c\n",optopt);
+           usage();
+       default:                                       /* should not reached */
+           usage();
+       }
+    }
+    /* ***********************************************************
+     * 
+     *          Options processing completed
+     *
+     *               Main code beginning
+     * 
+     * ***********************************************************/
+    if ((argc - optind) != 1) {          /* There must be remaing parameters */
+       printf("Wrong number of arguments %d\n", argc - optind);
+        usage();
+    }
+    mutex_file = tempnam("/tmp","mutex");
+    if ((mutex = CreateMutex(mutex_file)) == -1) {            /* get a Mutex */
+       perror("Cannot create mutex");
+       goto errmutex;
+    }
+    /* main loop */
+    shm_ptr = CreateShm(argv[1], size, 0644, 0);
+    if (shm_ptr == NULL) {
+       perror("Error creating shared memory");
+       goto errshared;
+    }
+    if (file_name) {
+       fd = open(file_name, O_RDONLY);
+    }
+    FullRead(fd, shm_ptr, size);
+//    RemoveShm(argv[1]);
+    RemoveMutex(mutex_file);
+    exit(0);
+ errshared:
+    RemoveShm(argv[1]);
+    RemoveMutex(mutex_file);
+ errmutex:
+    exit(1);
+}
+/*
+ * routine to print usage info and exit
+ */
+void usage(void) {
+    printf("Program myls: list file in a directory \n");
+    printf("Usage:\n");
+    printf("  WriteShm [-h] [-s size] [-f file] name \n");
+    printf("  -h          print this help\n");
+    printf("  -s size     size of segment \n");
+    printf("  -f file     filename to read contents \n");
+    exit(1);
+}