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digitalmars.D.learn - Problem getting Cimgui to work

reply Thomas <earthwormjimmy gmx.at> writes:
Hi guys!

I need some help or advice about Cimgui (a C-API for Imgui) 
because I have no idea how to get it working.

First, I'm new to D (only a few weeks) and still learning. I have 

got into my focus.
I am working on Manjaro Linux btw.

Since 2 weeks I am working on a small project of mine to test the 
SDL2 functions with derelict. Until now everything worked just 
fine and I got my first window in SDL.
For this I have installed all SDL library and development files 
with the package manager of Manjaro Linux. Even GLFW.

To fill the SDL window with some widgets I have decided to try 
Imgui via Cimgui.
My first approach was to use the derelict-imgui version 0.9.4 
over DUB.
import derelict.imgui.imgui; has been accepted yet, but 
DerelictImgui.load(); not

While compiling I got the following error message:

derelict.util.exception.SharedLibLoadException ../../.dub/packages/derelict-util-3.0.0-beta.2/derelict-util/source/derelict/ut
l/sharedlib.d(158): Failed to load one or more shared libraries:
	cimgui.so - cimgui.so: cannot open shared object file: No such 
file or directory

so Cimgui was missing..

Ok, so in a second attempt I downloaded Cimgui as a ZIP and also 
the Imgui files from the homepage into the appropriate directory 
and unzipped them. First, the compiling via make doesn't wanted 
to compile:


cimgui.cpp: In Funktion »void 
ImGuiTextBuffer_append(ImGuiTextBuffer*, const char*, ...)«:
cimgui.cpp:1716:13: Fehler: »struct ImGuiTextBuffer« hat kein 
Element namens »appendv«; meinten Sie »appendf«?
      buffer->appendv(fmt, args);


Translated from german -> "there is no element appendv in 
ImGuiTextBuffer"

So I changed the code myself on that position by replacing 
"appendv" with "appendf"
That worked fine. But next problem was this:


/usr/bin/ld: ../imgui/imgui.o: relocation R_X86_64_PC32 against 
symbol `_ZN6ImVec2C1Eff' can not be used when making a shared 
object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value


After some research I found out it meant that the imgui files had 
not been compiled with -fPIC to be used as a shared library. So I 
deleted all .o files in the imgui directory and recompiled
imgui.cpp
imgui_draw.cpp and
imgui_demo.cpp
each with "g++ -c -fPIC -pie"
So I copied the new compiled .o files to the cimgui project and 
recompiled it again.
This time it worked without problems :-)

The new shared library file cimgui.so moved to my project 
directory and exported LD_LIBRARY_PATH so it could be found by 
the compiler.
This time the compiler cried this error:


derelict.util.exception.SymbolLoadException ../../.dub/packages/derelict-util-3.0.0-beta.2/derelict-util/source/derelict/ut
l/sharedlib.d(181): Failed to load symbol igPushIdPtr from shared library
cimgui.so
----------------
??:? void* 
derelict.util.sharedlib.SharedLib.loadSymbol(immutable(char)[], 
bool) [0xcfec77a6]
??:? void* 
derelict.util.loader.SharedLibLoader.loadSymbol(immutable(char)[], bool)
[0xcfec5cce]
??:? void derelict.util.loader.SharedLibLoader.bindFunc(void**, 
immutable(char)[], bool) [0xcfec5978]
??:? void derelict.imgui.imgui.DerelictImguiLoader.loadSymbols() 
[0xcfebe7a5]
??:? void 
derelict.util.loader.SharedLibLoader.load(immutable(char)[][]) 
[0xcfec5b4e]
??:? void 
derelict.util.loader.SharedLibLoader.load(immutable(char)[]) 
[0xcfec5ac8]
??:? void derelict.util.loader.SharedLibLoader.load() [0xcfec59ab]
??:? _Dmain [0xcfeae0af]
Program exited with code 1


After some research again I found a workaround on the Derelict 
Util homepage:



import derelict.util.exception : ShouldThrow;

ShouldThrow myMissingSymbCB( string symbolName )
{
		if ( symbolName == "igSetNextWindowPosCenter" ||
		     symbolName == "igAlignFirstTextHeightToWidgets" ||
		     symbolName == "igPushIdStr" ||
		     symbolName == "igPushIdStrRange" )
		{
			return ShouldThrow.No;
		}
		else
		{
			return ShouldThrow.Yes;
		}
}

int main()
{
     DerelictImgui.missingSymbolCallback = &myMissingSymbCB;
     DerelictImgui.load();
}


But with each attempt to compile my project with "dub" by adding 
the next symbol name into the list above a new symbol fails to 
load. Again and again.

Since 1 week I tried several ways to get the libray to work. 
Unfortunately without success.

Because I couldn't find any relevant information on the internet 
about this problem I hope to get a solution here. Maybe someone 
(an Cimgui expert here?) can give me a step by step instruction 
how to compile the library properly ?

Thank you!
Dec 06 2017
parent reply drug <drug2004 bk.ru> writes:
06.12.2017 20:51, Thomas пишет:

 Hi guys!
 
 I need some help or advice about Cimgui (a C-API for Imgui) because I 
 have no idea how to get it working.
 
 First, I'm new to D (only a few weeks) and still learning. I have a 

 my focus.
 I am working on Manjaro Linux btw.
 
 Since 2 weeks I am working on a small project of mine to test the SDL2 
 functions with derelict. Until now everything worked just fine and I got 
 my first window in SDL.
 For this I have installed all SDL library and development files with the 
 package manager of Manjaro Linux. Even GLFW.
 
 To fill the SDL window with some widgets I have decided to try Imgui via 
 Cimgui.
 My first approach was to use the derelict-imgui version 0.9.4 over DUB.
 import derelict.imgui.imgui; has been accepted yet, but 
 DerelictImgui.load(); not
 
 While compiling I got the following error message:
 
 derelict.util.exception.SharedLibLoadException ../../.dub/packages/derelict-util-3.0.0-beta.2/derelict-util/source/derelict/ut
l/sharedlib.d(158): 
 Failed to load one or more shared libraries:
      cimgui.so - cimgui.so: cannot open shared object file: No such file 
 or directory
 
 so Cimgui was missing..
 
 Ok, so in a second attempt I downloaded Cimgui as a ZIP and also the 
 Imgui files from the homepage into the appropriate directory and 
 unzipped them. First, the compiling via make doesn't wanted to compile:
 
 
 cimgui.cpp: In Funktion »void ImGuiTextBuffer_append(ImGuiTextBuffer*, 
 const char*, ...)«:
 cimgui.cpp:1716:13: Fehler: »struct ImGuiTextBuffer« hat kein Element 
 namens »appendv«; meinten Sie »appendf«?
       buffer->appendv(fmt, args);
 
 
 Translated from german -> "there is no element appendv in ImGuiTextBuffer"
 
 So I changed the code myself on that position by replacing "appendv" 
 with "appendf"
 That worked fine. But next problem was this:
 
 
 /usr/bin/ld: ../imgui/imgui.o: relocation R_X86_64_PC32 against symbol 
 `_ZN6ImVec2C1Eff' can not be used when making a shared object; recompile 
 with -fPIC
 /usr/bin/ld: final link failed: Bad value
 
 
 After some research I found out it meant that the imgui files had not 
 been compiled with -fPIC to be used as a shared library. So I deleted 
 all .o files in the imgui directory and recompiled
 imgui.cpp
 imgui_draw.cpp and
 imgui_demo.cpp
 each with "g++ -c -fPIC -pie"
 So I copied the new compiled .o files to the cimgui project and 
 recompiled it again.
 This time it worked without problems :-)
 
 The new shared library file cimgui.so moved to my project directory and 
 exported LD_LIBRARY_PATH so it could be found by the compiler.
 This time the compiler cried this error:
 
 
 derelict.util.exception.SymbolLoadException ../../.dub/packages/derelict-util-3.0.0-beta.2/derelict-util/source/derelict/ut
l/sharedlib.d(181): 
 Failed to load symbol igPushIdPtr from shared library cimgui.so
 ----------------
 ??:? void* 
 derelict.util.sharedlib.SharedLib.loadSymbol(immutable(char)[], bool) 
 [0xcfec77a6]
 ??:? void* 
 derelict.util.loader.SharedLibLoader.loadSymbol(immutable(char)[], bool) 
 [0xcfec5cce]
 ??:? void derelict.util.loader.SharedLibLoader.bindFunc(void**, 
 immutable(char)[], bool) [0xcfec5978]
 ??:? void derelict.imgui.imgui.DerelictImguiLoader.loadSymbols() 
 [0xcfebe7a5]
 ??:? void derelict.util.loader.SharedLibLoader.load(immutable(char)[][]) 
 [0xcfec5b4e]
 ??:? void derelict.util.loader.SharedLibLoader.load(immutable(char)[]) 
 [0xcfec5ac8]
 ??:? void derelict.util.loader.SharedLibLoader.load() [0xcfec59ab]
 ??:? _Dmain [0xcfeae0af]
 Program exited with code 1
 
 
 After some research again I found a workaround on the Derelict Util 
 homepage:
 
 
 
 import derelict.util.exception : ShouldThrow;
 
 ShouldThrow myMissingSymbCB( string symbolName )
 {
          if ( symbolName == "igSetNextWindowPosCenter" ||
               symbolName == "igAlignFirstTextHeightToWidgets" ||
               symbolName == "igPushIdStr" ||
               symbolName == "igPushIdStrRange" )
          {
              return ShouldThrow.No;
          }
          else
          {
              return ShouldThrow.Yes;
          }
 }
 
 int main()
 {
      DerelictImgui.missingSymbolCallback = &myMissingSymbCB;
      DerelictImgui.load();
 }
 
 
 But with each attempt to compile my project with "dub" by adding the 
 next symbol name into the list above a new symbol fails to load. Again 
 and again.
 
 Since 1 week I tried several ways to get the libray to work. 
 Unfortunately without success.
 
 Because I couldn't find any relevant information on the internet about 
 this problem I hope to get a solution here. Maybe someone (an Cimgui 
 expert here?) can give me a step by step instruction how to compile the 
 library properly ?
 
 Thank you!


Could you describe what dub package you tried to build first of all? It 
helps to reproduce your case.
Dec 06 2017
next sibling parent reply drug <drug2004 bk.ru> writes:
probably this can help you
https://github.com/drug007/timespatial
this project uses cimgui by means of derelict-imgui
Dec 06 2017
parent reply Thomas <earthwormjimmy gmx.at> writes:
On Wednesday, 6 December 2017 at 18:27:20 UTC, drug wrote:

 probably this can help you
 https://github.com/drug007/timespatial
 this project uses cimgui by means of derelict-imgui


Hi, thank you. I tried it and first it seemed to work, but after 
I entered "dub build config=demo" following error messages 
occured:

Fetching taggedalgebraic 0.10.7 (getting selected version)...
Fetching msgpack-d 1.0.0-beta.6 (getting selected version)...
Fetching d2sqlite3 0.9.8 (getting selected version)...
Fetching gfm 6.1.4 (getting selected version)...
Fetching dstats 1.0.3 (getting selected version)...
Fetching emsi_containers 0.5.3 (getting selected version)...
Fetching color 0.0.5 (getting selected version)...
Performing "debug" build using dmd for x86_64.
d2sqlite3 0.9.8: building configuration "with-lib"...
derelict-util 2.0.6: target for configuration "library" is up to 
date.
derelict-imgui ~master: building configuration "library"...
DerelictImgui/source/derelict/imgui/funcs.d(38,12): Deprecation: 
module std.c.stdarg is deprecated - Import core.stdc.stdarg 
instead
dstats 1.0.3: building configuration "library"...
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(1056,8):
Deprecation: dstats.summary.reduce is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(1056,8):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(1106,38):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(1109,31):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(2119,20):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(2226,15):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/regress.d(2233,12):
Deprecation: dstats.alloc.max is not visible from module regress
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1458,24):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1461,24):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1501,9):
Deprecation: dstats.summary.swap is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1502,23):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1799,24):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1802,24):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(1821,9):
Deprecation: dstats.summary.swap is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(3594,20):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(3596,20):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(3637,31):
Deprecation: dstats.summary.min is not visible from module tests
../../.dub/packages/dstats-1.0.3/dstats/source/dstats/tests.d(3646,9):
Deprecation: dstats.summary.swap is not visible from module tests
emsi_containers 0.5.3: building configuration "library"...
gfm:math 6.1.4: building configuration "library"...
derelict-gl3 1.0.23: target for configuration "library" is up to 
date.
gfm:opengl 6.1.4: building configuration "library"...
derelict-sdl2 1.9.7: building configuration "library"...
gfm:sdl2 6.1.4: building configuration "library"...
msgpack-d 1.0.0-beta.6: building configuration "library"...
taggedalgebraic 0.10.7: building configuration "library"...
timespatial 0.0.3+commit.167.gd82e6dd: building configuration 
"demo"...
DerelictImgui/source/derelict/imgui/funcs.d(38,12): Deprecation: 
module std.c.stdarg is deprecated - Import core.stdc.stdarg 
instead
/usr/include/dlang/dmd/std/conv.d(4502,34): Error: cannot cast 
expression chunk.idx.idx of type TreeMap!(uint, DataSet, 
Mallocator, "a<b", false, 64LU) to void*
/usr/include/dlang/dmd/std/conv.d(4604,21): Error: template 
instance std.conv.emplace!(DataSource, DataSourceHeader) error 
instantiating
/usr/include/dlang/dmd/std/experimental/allocator/package.d(672,52):       
instantiated from here: emplace!(DataSource, DataSourceHeader)
demo/app.d(208,55):        instantiated from here: 
make!(DataSource, StatsCollector!(Region!(Mallocator, 16u, 
cast(Flag)false), 262143LU, 262143LU)*, DataSourceHeader)
source/data_index.d(143,27):        instantiated from here: 
processElement!(Tuple!(int, "index", TaggedAlgebraic!(Base), 
"value"))
source/data_index.d(136,14):        ... (1 instantiations, -v to 
show) ...
source/data_index.d(391,25):        instantiated from here: 
__ctor!(Tuple!(int, "index", TaggedAlgebraic!(Base), "value")[])
demo/app.d(91,20):        instantiated from here: 
DataIndex!(Tuple!(int, "index", TaggedAlgebraic!(Base), 
"value")[], DataSourceHeader, DataSetHeader, DataElement, 
ProcessElement)
/usr/include/dlang/dmd/std/experimental/allocator/package.d(689,49): Error:
forward reference to inferred return type of function call 'function ()
{
alloc.deallocate(m);
}
()'
/usr/include/dlang/dmd/std/conv.d(4502,34): Error: cannot cast 
expression chunk.idx of type DynamicArray!(DataElement, 
Mallocator, false) to void*
/usr/include/dlang/dmd/std/conv.d(4604,21): Error: template 
instance std.conv.emplace!(DataSet, DataSetHeader) error 
instantiating
/usr/include/dlang/dmd/std/experimental/allocator/package.d(672,52):       
instantiated from here: emplace!(DataSet, DataSetHeader)
demo/app.d(219,49):        instantiated from here: make!(DataSet, 
StatsCollector!(Region!(Mallocator, 16u, cast(Flag)false), 
262143LU, 262143LU)*, DataSetHeader)
source/data_index.d(143,27):        instantiated from here: 
processElement!(Tuple!(int, "index", TaggedAlgebraic!(Base), 
"value"))
source/data_index.d(136,14):        ... (1 instantiations, -v to 
show) ...
source/data_index.d(391,25):        instantiated from here: 
__ctor!(Tuple!(int, "index", TaggedAlgebraic!(Base), "value")[])
demo/app.d(91,20):        instantiated from here: 
DataIndex!(Tuple!(int, "index", TaggedAlgebraic!(Base), 
"value")[], DataSourceHeader, DataSetHeader, DataElement, 
ProcessElement)
/usr/include/dlang/dmd/std/experimental/allocator/package.d(689,49): Error:
forward reference to inferred return type of function call 'function ()
{
alloc.deallocate(m);
}
()'
source/default_viewer.d(83,20): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(83,20): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(84,23): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(96,20): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(96,20): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(97,23): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(814,27): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
source/default_viewer.d(814,27): Deprecation: struct 
std.datetime.StopWatch is deprecated - Use 
std.datetime.stopwatch.StopWatch.
dmd failed with exit code 1.
Dec 06 2017
parent reply drug <drug2004 bk.ru> writes:
I've check it before posting using old version dmd 2.073 and it works.
What dmd version you compile with?
Dec 06 2017
parent reply Thomas <earthwormjimmy gmx.at> writes:
On Wednesday, 6 December 2017 at 19:12:43 UTC, drug wrote:

 I've check it before posting using old version dmd 2.073 and it 
 works.
 What dmd version you compile with?


Hi. The newest as I know. Version 2.077.0   (64bit Version)

But the error messages in my last post don't seem to relate to my 
problem, but of some depricated stuff of dmd module "conv".

I am now analysing your way to implement Cimgui into your 
project. As far as I could find out till now youre using a script 
to clone the whole cimgui stuff into your project directory. I 
didn't know that this is possible :-)
The next difference I found is the -shared flag on compilation of 
the cimgui files. Maybe that is the big deal.
And at last point loading the shared lib is totaly different.

I will try it the same way. If it loads the shared library 
correct thats more than I could hope :-)

Thank you.
Dec 06 2017
parent reply Thomas <earthwormjimmy gmx.at> writes:
On Wednesday, 6 December 2017 at 19:37:54 UTC, Thomas wrote:

 On Wednesday, 6 December 2017 at 19:12:43 UTC, drug wrote:

 I've check it before posting using old version dmd 2.073 and 
 it works.
 What dmd version you compile with?


 Hi. The newest as I know. Version 2.077.0   (64bit Version)

 But the error messages in my last post don't seem to relate to 
 my problem, but of some depricated stuff of dmd module "conv".

 I am now analysing your way to implement Cimgui into your 
 project. As far as I could find out till now youre using a 
 script to clone the whole cimgui stuff into your project 
 directory. I didn't know that this is possible :-)
 The next difference I found is the -shared flag on compilation 
 of the cimgui files. Maybe that is the big deal.
 And at last point loading the shared lib is totaly different.

 I will try it the same way. If it loads the shared library 
 correct thats more than I could hope :-)

 Thank you.



I tried it now your way. First I cloned cimgui + imgui inside my 
project the same way with the build.sh script. That worked out of 
the box.
Next I wrote a new app.d file only using the necessary code for 
testing:


import std.stdio;
import derelict.imgui.imgui: DerelictImgui;

int main()
{
    DerelictImgui.load("DerelictImgui/cimgui/cimgui/cimgui.so");
    return 0;
}


After compiling with dub again the same problem with symbol names 
->

"Failed to load symbol igSetNextWindowSizeConstraints from shared 
library DerelictImgui/cimgui/cimgui/cimgui.so"

strange..
Dec 06 2017
parent reply Thomas <earthwormjimmy gmx.at> writes:
Hi folks!

I got it to work, but honestly I don't know why.. :-)

1. clone project imgui_d_test with git
2. subloading the base cimgui stuff by command: git submodule 
update --init --recursive
3. enter cimgui directory and enter make
4. after that dub doesn't work properly, you have to edit app.d
replace DerelictImgui.load(); with 
DerelictImgui.load("/..pathToFile../cimgui.so");

Now it works for me! :-)

testet on dmd 2.077.0

 drug007: I have testet the new generated cimgui.so file from 
imgui_d_test project on your and mine project and it worked. 
Replacing the file with the shared library generated inside my or 
your project, the build will not run -> same problem with loading 
the symbol names.
Hmm.. maybe they did some corrections in project imgui in the 
last couple of hours ?
Whatever.. i will take the new cimgui.so file and use it.

Thank you for your time!
Dec 06 2017
parent reply Mike Parker <aldacron gmail.com> writes:
On Wednesday, 6 December 2017 at 21:21:11 UTC, Thomas wrote:

 Hi folks!

 I got it to work, but honestly I don't know why.. :-)


Glad you got it working. I wanted to reply earlier but I was on 
my phone when I first saw this thread. So now instead of helping 
you solve the problem, I'll throw in a few words to hopefully 
shed some light on why it worked and help you more easily solve 
similar issues if they arise in the future.


 1. clone project imgui_d_test with git
 2. subloading the base cimgui stuff by command: git submodule 
 update --init --recursive


The short answer is that this step is why it worked. I'll 
elaborate below.


 3. enter cimgui directory and enter make
 4. after that dub doesn't work properly, you have to edit app.d
 replace DerelictImgui.load(); with 
 DerelictImgui.load("/..pathToFile../cimgui.so");


You shouldn't ever have to do this if things are properly 
configured.



 Hmm.. maybe they did some corrections in project imgui in the 
 last couple of hours ?


Not quite :-) But the root of the problem does, indeed, come down 
to changes in imgui. I'll quote from your previous posts to show 
how to solve the sort of problem you encountered.


 Ok, so in a second attempt I downloaded Cimgui as a ZIP and 
 also the Imgui files from the homepage into the appropriate 
 directory and unzipped them.


This was the root mistake. Whenever you are using a D binding to 
a C library, no matter if it's an official Derelict package, an 
"unofficial" package (i.e., not one maintained as part of the 
DerelictOrg group, such as derelict-imgui), a Deimos package, or 
something else, always, always, always make sure the version of 
the C library you are using matches the version the binding 
supports. Some Derelict packages, like DerelictSDL2, support 
multiple versions of their C library via DerelictUtil's 
SharedLibVersion feature. Most do not.

So the thing to do is to look at the project's code.dlang.org 
page and see if the info you need is there. If not, follow the 
link to the source repository on that page and look for any and 
all documentation you can find to see which version of the 
binding requires which version of the C library. What happens if 
there's a version mismatch? This:


 This time the compiler cried this error:



 derelict.util.exception.SymbolLoadException ../../.dub/packages/derelict-util-3.0.0-beta.2/derelict-util/source/derelict/ut
l/sharedlib.d(181): Failed to load symbol igPushIdPtr from shared library
cimgui.so


A SymbolLoadException almost always indicates that your version 
of the C library is different (usually older) from the one the 
Derelict binding expects (in rare cases it can be a corrupt 
library). The solution is to double check that your versions 
match. It usually helps to dig into the change logs/release notes 
of the C library to see if/when any functions were added or 
removed. That way you can figure out if the binding is outdated, 
or if you need an older/newer version of the C library.


 After some research again I found a workaround on the Derelict 
 Util homepage:


No, you did not find a workaround :-) The selective loading 
mechanism is not intended as a workaround for missing symbols. 
It's intended to be used when you want to support multiple 
versions of a C library (the SharedLibVersion feature uses it 
internally), or when the C library on the user's system might be 
compiled with and without certain features you don't care about. 
If you don't know the details of the C library or the potential 
consequences of ignoring any given set of functions, you 
shouldn't be using this feature. I need to make that clear in the 
documentation.


 Unfortunately there is no DUB for Cimgui itself


Cimgui is a C library and DUB does not support building C 
libraries.

===================

So, why did it work for you? From what I can gather, looking at 
the DerelictIMGUI repo, we see it's implemented against CImgui 
1.5.0. Looking at CImgui shows it has been updated to 1.52, which 
is implemented against imgui 1.52. Looking at the release notes 
for imgui 1.51 and 1.52, we can find several breaking changes 
since 1.50. The reason you finally got it to worked is because 
the submodule tree from DerelictIMGUI gave you version 1.50 of 
CImgui and Imgui.

So the steps should be:

checkout imgui 1.50
checkout cimgui 1.50
Build both
Put them on your system library path

Then you should be set to use DerelictIMGUI without the need to 
modify its package recipe.
Dec 06 2017
parent Thomas <earthwormjimmy gmx.at> writes:
 So the steps should be:

 checkout imgui 1.50
 checkout cimgui 1.50
 Build both
 Put them on your system library path

 Then you should be set to use DerelictIMGUI without the need to 
 modify its package recipe.



Thank you for your very very good description what was going on 
and how everything relate together! I will watch closely the 
version numbers from now on :-)

Best wishes!
Dec 07 2017
prev sibling parent Thomas <earthwormjimmy gmx.at> writes:
 Could you describe what dub package you tried to build first of 
 all? It helps to reproduce your case.


Hello.

In my personal project folder I only have:
derelict-sdl2   version="~>3.1.0-alpha.2"
derelict-imgui  version="~>0.9.4"

Then I realized that I needed the shared library file cimgui.so

Unfortunately there is no DUB for Cimgui itself, so I downloaded 
it via ZIP + the Imgui ZIP from the homepage
https://github.com/Extrawurst/cimgui/archive/master.zip  and
https://github.com/ocornut/imgui/archive/master.zip

Extracted and copied the imgui files into the cimgui/imgui 
directory, because the make file of cimgui needet it. The first 
compiled cimgui.so file didn't work because the same problem with 
the symbol names at the end of my last post.

So I deleted the Cimgui + Imgui directory again and cloned it by 
GIT this time.
Compilation didn't work because of the -fPIC problem. So I 
compiled the imgui .cpp files by hand with "g++ -c -fPIC -pie" to 
be able to compile cimgui.

Thats all.

Thank you for your time!
Dec 06 2017