PureBasic Forums - English

Hello everybody,

I need a little (a lot) of help using the pdfium lib.
I am, as the French say, a Sunday programmer and my technical capabilites are very limited in external library usage.

What I'm looking for is to retrieve text areas from PDF files.
After some research, I found this post

As the github link was no longer valid, I turned to this one:

In this package, I found the pdfium.dll.lib file. From there, I tried two approaches:

1) Follow seeker's instructions

seeker wrote:polib %1.dll /machine:X64 /out:%1.lib

But when I run its example code with

Import "MyCustomDir:\pdfium.lib"

an error message "LINK: fatal error LNK1181 canno't open file - "MyCustomDir:\pdfium.lib"" appears.

2) Use the original pdfium.dll.lib provided in the package with

Import "MyCustomDir:\pdfium.dll.lib"

But same error message!

Does anyone know why this error occurs?
Where am I doing (surely ) something wrong?

Thanks.

PS : Oops! I forgot to mention that I'm using Win10-x64 & PB6.10 b1

Follow infratec's instructions here:
https://www.purebasic.fr/english/viewto ... 10#p553210


Norm.

@normeus

normeus wrote: Follow infratec's instructions here:

Thanks for you response.

But I still have a problem and errors.

Where do I put this lib?
1) When I put it in the source code folder
  • with I get the following message: "Can't run the code because pdfium.dll.lib can't be found. Reinstalling the program may correct this problem."
[/quote]
  • with I get the following message: "LINK: fatal error LNK1181 canno't open file - "MyCustomDir:\pdfium.dll.lib"

2) When I put it in the PB libraries folder ("PB folder\PureLibraries\Windows\Libraries\")
  • with I get the following message too: "Can't run the code because pdfium.dll.lib can't be found. Reinstalling the program may correct this problem."

3) When I put it in the user libraries folder ("PB folder\PureLibraries\UserLibraries\")
  • with I get the following message: "LINK: fatal error LNK1181 canno't open file - "MyCustomDir:\pdfium.dll.lib"


It make me crazy

As far as I know, there is no static lib file.

My version uses the pdfium.dll.lib to get the informations about the functions inside of the dll.
So your exe needs the pdfium.dll beside.

At compile time the file pdfium.dll.lib should be in the folder of your pb file.

For development in such a case, you should enable 'create temp executable in source directory' (not the exact words).
I use this in general.
Then you can put the lib and the dll file beside your sourc code.

Hello Infratec,

infratec wrote: Thu Jan 11, 2024 12:35 pm At compile time the file pdfium.dll.lib should be in the folder of your pb file.

Thank you, firstly, for your code and, secondly, for your reply.

If I understand correctly, the pdfium.dll.lib and pdfium.dll files "must" both be in the same folder ?!
So the call to polib.exe would be useless?

I can't test now but I'll try as soon as I can.

Thanks again.

If you alreday own the lib file and the dll file, then you don't need to call something.

Newbie's question: There is a way to have only one file (pdfium.dll)?

you need both files.
pdfium.dll.lib ( symbol table that "describes" the contents of pdfium.dll )
pdfium.dll ( the actual dll)

Three files total if you include your exe.

I tried Infratec's code today and it worked great: (https://www.purebasic.fr/english/viewto ... 10#p553210

1.- Downloaded "pdfium-win-x64.tgz" from https://github.com/bblanchon/pdfium-binaries.
2.- Extracted two files pdfium.dll and pdfium.dll.lib and saved them at the same location were the source code is located "E:\pb\pdfium\" in my case.
3.- Made sure that the setting for "Create temporary executable in the source directory" in File->Preferences->Compiler->Defaults was enabled.
4.- I downloaded the purebasic book pdf from: https://www.purebasic.com/documentation ... cSmall.pdf
5.- I was able to open PureBasic.pdf and read text from the pages no problem.

Norm

normeus wrote: you need both files.

Ok.
One last question (I don't want to seem very insistent but it's not clear in my mind): Why do some codes use a dll and don't need a .dll.lib file?

normeus wrote: 1.- 5.

In the meantime, I've already done it, tested it and can confirm that it works correctly . Thanks anyway for your reply

In this case "dll.lib" is like a catalog of functions for the "dll" file.
Once you are happy with your program and created an exe file then you do not need the "dll.lib" file anymore, because it is only used by the compiler/linker to know where the different functions are located in the "dll" file.

You only need your program and the dll file in the program's directory for it to run once compiled. Sorry if that was not mentioned before.

for an explanation of "lib" and "dll" take a look at stackoverflow:

this question:
https://stackoverflow.com/questions/913 ... at-and-why
and also this question:
https://stackoverflow.com/questions/311 ... inked-mean

Happy Coding!
Norm.

normeus wrote: In this case "dll.lib" is like a catalog of functions for the "dll" file.

Thanks a lot for this explanation.
I can see a bit more clearly now (as Jimmy Cliff used to say ).

So, if I've understood correctly, for example, the .lib in the PureLibraries\Windows\Libraries folder are the indexes of the Windows dlls procedures needed to compile... I'm right?

boddhi wrote: Thu Jan 11, 2024 11:08 pm Newbie's question: There is a way to have only one file (pdfium.dll)?

Yes.
But the lib file is not needed for execution.

You can use OpenLibrary(), Prototypes and GetFunction().
Then you don't need the lib file. But you have to create the Prototypes of the imported functions.

@infratec

OK, OK, as we said in French, I'm starting to attach the wagons to the locomotive.