The rationale for the fixinclude ioctl macro wrapper is, as far as I can
tell (https://gcc.gnu.org/ml/gcc-patches/2012-09/msg01619.html)
Fix 2: Add hack for ioctl() on VxWorks.
ioctl() is supposed to be variadic, but VxWorks only has a three
argument version with the third argument of type int. This messes up
when the third argument is not implicitly convertible to int. This
adds a macro which wraps around ioctl() and explicitly casts the third
argument to an int. This way, the most common use case of ioctl (with
a const char * for the third argument) will compile in C++, where
pointers must be explicitly casted to int.
However, we have existing C++ code that calls the ioctl function via
::ioctl(foo, bar, baz)
and obviously this breaks when it gets expanded to
::(ioctl)(foo, bar, (int)(baz))
Since the GNU C preprocessor already prevents recursive expansion of
function-like macros, the parentheses around ioctl are unnecessary.
Incidentally, there is also a macro sioIoctl() in the vxworks sioLib.h
header that expands to
((pSioChan)->pDrvFuncs->ioctl (pSioChan, cmd, arg))
which also breaks when that gets further expanded to
((pSioChan)->pDrvFuncs->(ioctl) (pSioChan, cmd, (int)(arg)))
This patch partly fixes that issue as well, but the third argument to
the pDrvFuncs->ioctl method should be void*, so the cast to (int) is
slightly annoying. Internally, we've simply patched the sioIoctl macro:
(((pSioChan)->pDrvFuncs->ioctl) (pSioChan, cmd, arg))
==changelog==
fixincludes/
* inclhack.def (vxworks_ioctl_macro): Remove parentheses from
expansion of ioctl macro.
* fixincl.x: Regenerate.
---
fixincludes/inclhack.def | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fixincludes/inclhack.def b/fixincludes/inclhack.def
index c1f5a13eda4..f7d2124ba74 100644
--- a/fixincludes/inclhack.def
+++ b/fixincludes/inclhack.def
@@ -4902,7 +4902,7 @@ fix = {
c_fix = format;
c_fix_arg = "%0\n"
- "#define ioctl(fd, func, arg) (ioctl)(fd, func, (int)(arg))\n";
+ "#define ioctl(fd, func, arg) ioctl(fd, func, (int)(arg))\n";
c_fix_arg = "extern[\t ]+int[\t ]+ioctl[\t ]*\\([\t ,[:alnum:]]*\\);";
test_text = "extern int ioctl ( int asdf1234, int jkl , int qwerty ) ;";
--
2.16.4
