This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(118.4, 84%, 21%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ETW%3C/text%3E%3C/svg%3E)
I'm having trouble running my program. It shows the following dialog:
The procedure entry point nlopt_add_equality_constraint could not be located in the dynamic link library G:\WorkDir\Projects\xxxxxxx\x64\Debug\xxxxxxx.exe.
nlopt_add_equality_constraint should be in libnlopt.dll, and I checked it, the export is ok. So I turned on "Show loader Snaps" flag and got some log:
https://pastebin.com/p381nCXg
Line 1153
DebugString: "10afc:2818 @ 197842421 - LdrpNameToOrdinal - WARNING: Procedure "nlopt_add_equality_constraint" could not be located in DLL at base 0x000000006D7C0000."
Line 578 and 579
DLL Loaded: 000000006D7C0000 G:\WorkDir\Projects\xxxxxxx\x64\Debug\libopenblas.dll
DLL Loaded: 000000006A740000 G:\WorkDir\Projects\xxxxxxx\x64\Debug\libnlopt.dll
The log shows that it tries to load nlopt_add_equality_constraint from the wrong DLL. libnlopt was compiled with 64bit mingw. It was working, and the problem happened for some unknown reason.
I tried to recompile nlopt and update the lib and dll, the problem is still there. Is there any other cause?
Update:
Seems that if I enable one of them(nlopt/openblas), it works, but if both are enabled, the imports get messed up.
I made a minimum example, use x64 Debug to compile.
https://1drv.ms/u/s!AkqxTizATCPayWNinQzbqmlu2UIS?e=bl9bKx
Update2
I removed the c++ code and calls openblas/nlopt's C api directly. Note the changes sometimes needs "rebuild" to take effect.
https://1drv.ms/u/s!AkqxTizATCPayWT3LjElc5e7zltX?e=2rJgIB
Also here's the import shown by Dependencies
only nlopt used, working
only openblas used, working, note the import name is correct.
both used, not working, the import of openblas is the same as nlopt (overwritten?).
Thanks
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(201.6, 57.00000000000001%, 29%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMY%3C/text%3E%3C/svg%3E)
@ty wang Can you provide some information about your Visual Studio version and the settings made to load the DLL? Also, it will be better to provide a minimal reproducible example. For you reference: Create a client app that uses the DLL.
Hi, @ty wang
Since I can't see the code of the DLL, I tried not to use the namespace, and instead use codes such as nlopt::. Also, I modified the code m, and it can run.
Best regards,
Minxin Yu
If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
Removing m*m actually removes the dependency from openblas, but the problem only happens when both libraries are used. Please see my update2, the problem is more obvious in it.
Since the sample1 mixed namespace also make the error, you need to check whether there are two functions with the same name in the two DLLs just like that in you picture .
I don't understand how the namespace causes error. In sample2, there are no namespace in it, but it still has the error.
The two dlls don't have any function with the same name. 
And by enabling only one of line 7/9 in sample 2 the exe works, so there can't be name conflict. I think this is a linker problem, could you kindly check if VS's linker can correctly handle libnlopt.dll.a and libopenblas.dll.a in the project? Or are there any problem with the libs?
I checked the way to add DLLs. After changing the .dll.a file to .lib file in propertities->Linker->input , it can run.
