[swift-dev] long double usage in swift

Saleem Abdulrasool compnerd at compnerd.org
Wed Mar 23 16:56:12 CDT 2016


On Wed, Mar 23, 2016 at 2:35 PM, Alex Blewitt <alex.blewitt at gmail.com>
wrote:

> Why not?
>
>
> https://github.com/apple/swift/blob/8d9ef80304d7b36e13619ea50e6e76f3ec9221ba/test/Inputs/clang-importer-sdk/usr/include/ctypes.h#L146
>


AIUI, Float80 isn't exactly applicable to this test (since I want an
explicit long double to be imported, not whatever the representation of
FP80 happens to be).  However, thanks for that pointer, it was able to help
me with my issue.  It seems that the clang importer explicitly excludes the
long double type from being mapped.  Since long double is made illegal, the
decl is pruned from the generated module, resulting in the unresolved
reference.


> On 23 Mar 2016, at 21:29, Saleem Abdulrasool <compnerd at compnerd.org>
> wrote:
>
> On Wed, Mar 23, 2016 at 2:28 PM, Alex Blewitt <alex.blewitt at gmail.com>
> wrote:
>
>> There’s a Float80 type, if you’re looking for an 80-bit floating point
>> value.
>>
>
> Im explicitly trying to import a call from C through the clang-importer
> (to ensure that long doubles are imported correctly).  As such,
> unfortunately, I don't think that the use of Float80 is appropriate in this
> case.
>
>
>> Alex
>>
>> > On 23 Mar 2016, at 21:25, Saleem Abdulrasool via swift-dev <
>> swift-dev at swift.org> wrote:
>> >
>> > Hi,
>> >
>> > I was looking at an ABI related issue on Windows.  In trying to
>> construct a test case, it seems that I am unable to import a declaration
>> using a long double into swift.  I was wondering if there is something
>> about long double usage in swift that I am unaware of.
>> >
>> > Inputs/abi.h:
>> >
>> > float fp32_call(void);
>> > double fp64_call(void);
>> > long double fp80_call(void);
>> >
>> > Inputs/module.map:
>> >
>> > module abi {
>> >   header "abi.h"
>> > }
>> >
>> > test.swift:
>> >
>> > %swift -I Inputs -parse %s
>> > import abi
>> >
>> > @inline(never)
>> > func blackhole<T>(t : T) { }
>> >
>> > func test_floating_point() {
>> > }
>> >
>> > Thanks!
>> >
>> > --
>> > Saleem Abdulrasool
>> > compnerd (at) compnerd (dot) org
>> > _______________________________________________
>> > swift-dev mailing list
>> > swift-dev at swift.org
>> > https://lists.swift.org/mailman/listinfo/swift-dev
>>
>>
>
>
> --
> Saleem Abdulrasool
> compnerd (at) compnerd (dot) org
>
>
>


-- 
Saleem Abdulrasool
compnerd (at) compnerd (dot) org
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