From: Nikolaus Rath <Nikolaus@rath.org>
Date: Thu, 25 May 2017 19:48:27 +0000 (-0700)
Subject: passthrough_ll: document that fuse_ino_t and uintptr_t sizes must match
X-Git-Tag: fuse-3.1.0~26
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=8641db4af724682fb1c922cbecf6c7e1dfe1a71c;p=qemu-gpiodev%2Flibfuse.git

passthrough_ll: document that fuse_ino_t and uintptr_t sizes must match

We can consider changing the code to drop the requirement if it
turns out that there's a system where this isn't given.

Fixes issue #167.
---

diff --git a/example/passthrough_ll.c b/example/passthrough_ll.c
index ac566ad..772a822 100644
--- a/example/passthrough_ll.c
+++ b/example/passthrough_ll.c
@@ -47,6 +47,19 @@
 #include <errno.h>
 #include <err.h>
 
+/* We are re-using pointers to our `struct lo_inode` and `struct
+   lo_dirp` elements as inodes. This means that we require uintptr_t
+   and fuse_ino_t to have the same size. The following incantation
+   defines a compile time assert for this requirement. */
+#if defined(__GNUC__) && (__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 6) && !defined __cplusplus
+_Static_assert(sizeof(fuse_ino_t) == sizeof(uintptr_t), "fuse: off_t must be 64bit");
+#else
+struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct \
+	{ unsigned _uintptr_to_must_hold_fuse_ino_t:
+			((sizeof(fuse_ino_t) == sizeof(uintptr_t)) ? 1 : -1); };
+#endif
+
+
 /* Compat stuff.  Doesn't make it work, just makes it compile. */
 #ifndef HAVE_FSTATAT
 #warning fstatat(2) needed by this program