$NetBSD: patch-libraries_unix_System_Posix_Signals.hsc,v 1.2 2019/12/29 16:59:09 pho Exp $
Suppress linker warnings about compatibility syscall wrappers by using
"capi" instead of "ccall". In Haskell FFI, "ccall" is actually an
interface to C ABI rather than C API. That is, GHC generates direct
references to the symbol even if it's actually defined as a cpp macro
or something like that, because GHC knows nothing about those macros
in foreign headers. Hence the following warnings:
.../libHSunix-22.214.171.124.a(Signals.o): In function `s4SG_info':
(.text+0x3a3e): warning: warning: reference to compatibility
sigsuspend(); include <signal.h> for correct reference
.../libHSunix-126.96.36.199.a(Signals.o): In function `s5uV_info':
(.text+0x6adb): warning: warning: reference to compatibility
sigpending(); include <signal.h> for correct reference
In other words, you can safely use "ccall" only when you are sure the
symbol you want to import is actually a symbol in the ABI sense, which
is not always the case for the POSIX API.
--- libraries/unix/System/Posix/Signals.hsc.orig 2015-07-23 22:04:56.000000000 +0000
@@ -603,7 +603,7 @@ awaitSignal maybe_sigset = do
-- XXX My manpage says it can also return EFAULT. And why is ignoring
-- EINTR the right thing to do?
-foreign import ccall unsafe "sigsuspend"
+foreign import capi unsafe "signal.h sigsuspend"
c_sigsuspend :: Ptr CSigset -> IO CInt
@@ -638,5 +638,5 @@ foreign import capi unsafe "signal.h sig
c_sigismember :: Ptr CSigset -> CInt -> IO CInt
#endif /* __HUGS__ */
-foreign import ccall unsafe "sigpending"
+foreign import capi unsafe "signal.h sigpending"
c_sigpending :: Ptr CSigset -> IO CInt