X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=include%2Flttng-share.h;h=5154b90a559c33e1c07dbecc90c0e02041ba4bf2;hp=38598bcea2de5b02b8868a45a3a4cce0bcd8a43f;hb=e848fc768a950acc1b823fcb139057a4fac1442a;hpb=3817e7df7aa29d8f52f1a4909b4fa6b660494323

diff --git a/include/lttng-share.h b/include/lttng-share.h
index 38598bcea..5154b90a5 100644
--- a/include/lttng-share.h
+++ b/include/lttng-share.h
@@ -1,24 +1,26 @@
 /*
- * Copyright (C) - 2011 - David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  *
- * 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; only version 2
- * of the License.
+ * 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; only version 2 of the License.
  *
- * 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.
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ * 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., 59 Temple
+ * Place - Suite 330, Boston, MA  02111-1307, USA.
  */
 
 #ifndef _LTTNG_SHARE_H
 #define _LTTNG_SHARE_H
 
+#include <stdlib.h>
+
 /* Default channel attributes */
 #define DEFAULT_CHANNEL_NAME            "channel0"
 #define DEFAULT_CHANNEL_OVERWRITE       0       /* usec */
@@ -42,4 +44,36 @@
 /* See lttng-kernel.h enum lttng_kernel_output for channel output */
 #define DEFAULT_KERNEL_CHANNEL_OUTPUT       LTTNG_EVENT_SPLICE
 
+/*
+ * Takes a pointer x and transform it so we can use it to access members
+ * without a function call. Here an example:
+ *
+ *    #define GET_SIZE(x) LTTNG_REF(x)->size
+ *
+ *    struct { int size; } s;
+ *
+ *    printf("size : %d\n", GET_SIZE(&s));
+ *
+ * For this example we can't use something like this for compatibility purpose
+ * since this will fail:
+ *
+ *    #define GET_SIZE(x) x->size;
+ *
+ * This is mostly use for the compatibility layer of lttng-tools. See
+ * poll/epoll for a good example. Since x can be on the stack or allocated
+ * memory using malloc(), we must use generic accessors for compat in order to
+ * *not* use a function to access members and not the variable name.
+ */
+#define LTTNG_REF(x) ((typeof(*x) *)(x))
+
+/*
+ * Memory allocation zeroed
+ */
+#define zmalloc(x) calloc(1, x)
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
+#endif
+
+
 #endif /* _LTTNG_SHARE_H */