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digitalmars.D.learn - pragma(linkerDirective,_) removes double quotes, dmd ignores LIB

reply NonNull <non-null use.startmail.com> writes:
Hello, using dmd 2.100.2 and ldc2 1.30.0, compiling to 64-bits, 
Windows 10.

pragma(linkerDirective,_) strips double quotation marks,

so how can a linker command line like

/LIBPATH:"Path/containing spaces/to/needed/libs"

be passed on to the linker via this pragma? Is this a bug?

Note: the libs in question are installed in locations not 
determined by me.

I worked around this by setting a LIB environment variable 
containing the extra path I needed, so I didn't need the pragma. 
But this only worked for ldc2; dmd still complained it cannot 
find the necessary, ignoring the LIB environment variable. Is 
this a bug?
Nov 27 2022
next sibling parent reply kinke <noone nowhere.com> writes:
For LDC, you shouldn't need any double quotes, the compiler 
quotes the linker flag if it contains spaces.
Nov 27 2022
next sibling parent NonNull <non-null use.startmail.com> writes:
On Sunday, 27 November 2022 at 17:37:50 UTC, kinke wrote:

 For LDC, you shouldn't need any double quotes, the compiler 
 quotes the linker flag if it contains spaces.


Didn't work for me with LDC:

This, which works at the command line with ```-L=```:

```enum LIBPATH = `/LIBPATH:"C:\Program Files (x86)\Windows 
Kits\NETFXSDK\4.7.2\Lib\um\x64"`;
pragma(linkerDirective, LIBPATH);```

gave this:

```warning LNK4229: invalid directive '/LIBPATH:C:\Program Files 
(x86)\Windows Kits\NETFXSDK\4.7.2\Lib\um\x64' encountered; 
ignored```

and without the double quotes gave this:

```fatal error LNK1276: invalid directive 'Files' found; does not 
start with '/'```

This, which also works at the command line with ```-L=```:

```enum LIBPATH = `"/LIBPATH:C:\Program Files (x86)\Windows 
Kits\NETFXSDK\4.7.2\Lib\um\x64"`;
pragma(linkerDirective, LIBPATH);```

gave this:

```warning LNK4229: invalid directive '/LIBPATH:C:\Program Files 
(x86)\Windows Kits\NETFXSDK\4.7.2\Lib\um\x64' encountered; 
ignored```

So double quotes are not arriving at the destination.
Nov 27 2022
prev sibling parent reply NonNull <non-null use.startmail.com> writes:
On Sunday, 27 November 2022 at 17:37:50 UTC, kinke wrote:

 For LDC, you shouldn't need any double quotes, the compiler 
 quotes the linker flag if it contains spaces.


In fact I cannot find any way (multiple double quotes, escaped 
double quotes, different combinations of these) to get any double 
quotes whatsoever into the linker command line via 
pragma(linkerDirective,_).

The linker always complains and the quoted error always contains 
no double quotes.

The behavior of ldc2 is identical to that of dmd with all 
attempts.

pragma(linkerDirective,_) is broken apparently.

Please confirm or show how to use.
Nov 28 2022
parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Monday, 28 November 2022 at 14:19:46 UTC, NonNull wrote:

 double quotes whatsoever into the linker command line via 
 pragma(linkerDirective,_).


linkerDirective doesn't add things to the linker command line at 
all.

https://dlang.org/spec/pragma.html#linkerDirective

"Implementation Defined: The string literal specifies a linker 
directive to be embedded in the generated object file. Linker 
directives are only supported for MS-COFF output. "


"embedded in the generated object file" is not "added to linker 
command line". Only some switches are supported for embedding and 
the syntax might be different. This is why the error message also 
says "invalid directive".

This is the Microsoft doc page for the feature the pragma uses:

https://learn.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?source=recommendations&view=msvc-170#linker

It looks like they actually removed some options in the recent 
update, I know /SUBSYSTEM used to work there too but it is no 
longer listed and there's people on the web saying it stopped 
working after updating to the 2022 visual studio. So yeah I think 
they removed support for that.

But /LIBPATH has never been supported as far as I know.

You'll want to use a build script/makefile/dub config/whatever to 
set linker command line options.
Nov 28 2022
parent NonNull <non-null use.startmail.com> writes:
On Monday, 28 November 2022 at 14:41:01 UTC, Adam D Ruppe wrote:

 This is the Microsoft doc page for the feature the pragma uses:

 https://learn.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?source=recommendations&view=msvc-170#linker

 It looks like they actually removed some options in the recent 
 update, I know /SUBSYSTEM used to work there too but it is no 
 longer listed and there's people on the web saying it stopped 
 working after updating to the 2022 visual studio. So yeah I 
 think they removed support for that.

 But /LIBPATH has never been supported as far as I know.


Aha! Thank you: the MS doc page is very informative. So
https://dlang.org/spec/pragma.html#linkerDirective
is not simply a mechanism that via the object file can get any 
directive eventually to the linker as if on the command line.

I've been completely successful using pragma(lib,_) but looking 
carefully I see that
https://dlang.org/spec/pragma.html#lib
contains highly significant clues under "implementation defined" 
when compared to "implementation defined" under
https://dlang.org/spec/pragma.html#linkerDirective

--- pragma(lib,_) in effect guarantees to get the information 
through to the linker. It is not restricted to MS-COFF, and is 
not restricted to passing the information through the object file 
but may use "other means" left unspecified.

--- pragma(linkerDirective,_) IS restricted in these ways as you 
made clear.

So by comparison I should have realized, taking the hint 
"restricted to MS-COFF" that the documentation for the MS linker 
about what directives can be embedded in object files was 
pertinent, because who knows what MS may permit?! The clues were 
all there. But I didn't catch on. Sorry about the kerfuffle.

I have now successfully used pragma(lib,_) with a full path to 
link what's needed without resorting to external build stuff. I 
just need one pragma(lib,_) per library.
Nov 28 2022
prev sibling parent reply NonNull <non-null use.startmail.com> writes:
On Sunday, 27 November 2022 at 17:26:37 UTC, NonNull wrote:

 I worked around this by setting a LIB environment variable 
 containing the extra path I needed, so I didn't need the 
 pragma. But this only worked for ldc2; dmd still complained it 
 cannot find the necessary, ignoring the LIB environment 
 variable. Is this a bug?


I set the LIB environment variable and now ```ldc2 main.d``` 
works. So I know LIB is set correctly.

But ```dmd main.d``` still has linking fail to find libraries at 
the location LIB.

I did both in a new console where ```echo %LIB%``` produced the 
expected path.

Any idea what may be going on with dmd?
Nov 28 2022
parent reply zjh <fqbqrr 163.com> writes:
On Monday, 28 November 2022 at 16:21:20 UTC, NonNull wrote:


 Any idea what may be going on with dmd?


use `sc.ini` like this:

```d
[Version]
version=7.51 Build 020

[Environment]
lj=E:\path
DFLAGS="-I% P%\..\..\src\phobos" 
"-I% P%\..\..\src\druntime\import" "-I%lj%\dimport"
LIB="% P%\..\lib"

```
Nov 28 2022
parent zjh <fqbqrr 163.com> writes:
On Tuesday, 29 November 2022 at 01:08:03 UTC, zjh wrote:

 ...



```d
[Environment64]
LIB=% P%\..\lib;%lj%\dku;
```
Nov 28 2022