Excel API for C/C++

goetz · wrote on 4 Dec 2010, 00:35

Does anyone know of a platform independent C or C++ library/API for reading and writing Excel™ files?

The native API from Microsoft is not an option, as it might not be installed on every machine we target nor is it available on Macs.

I know of jexcelapi for Java, but never heard of a similar lib for our beloved C++ :)

xsacha · wrote on 4 Dec 2010, 01:38

KSpread (part of KOffice) reads/writes Excel files. KSpread uses Qt (and KDE libs).

Have you checked to see how they do it?

andre · wrote on 4 Dec 2010, 10:34

Do you really need Excel output, or do you just need to output data that Excel can read?

If the latter is enough, considder a simpler format like csv. Otherwise, you may want to investigate either the .ods or the .xlsx format. Both are packed structures with XML files, but they are not simple I have heard. I never worked with them directly.

A last option that may be workable is to go through ODBC and QtSql. You can read and write Excel files that way, but of course there are limits to what you can do there.

goetz · wrote on 5 Dec 2010, 00:02

I've found some infos on the Excel 2003 XML format on "this page":http://blogs.msdn.com/b/brian_jones/archive/2005/06/27/433152.aspx. Could be a good start.

CSV ist not an option, it's very cumbersome to read and write correctly. And the users receiving the CSV must take care of the correct settings (charset, delimiter, enclosing quotes and all that). That's error prone and the support for it is a nightmare - we all are developers, aren't we? :-) Also we need it in both directions (import Excel sheets of our users into our database and generate spread sheets for the users filled with our data).

Unfortunately we also must support opening Excel files in the native (i.e. non-XML) format, otherwise we would had to convert them by hand. Giving xlsx to our users would be ok.

goetz · wrote on 5 Dec 2010, 01:12

We can have Jexcelapi on the server using java. No problem with that. This way we have to put everything to the server, but I want do do some things in the Qt/C++ based client.

xsacha · wrote on 5 Dec 2010, 04:03

[quote author="Volker" date="1291507360"]Unfortunately we also must support opening Excel files in the native (i.e. non-XML) format, otherwise we would had to convert them by hand. Giving xlsx to our users would be ok.[/quote]

I believe Microsoft has a tool for converting non-XML to XML. You may be able to use it in a batch process.

So you only need to get info out? You don't need to be able to edit it and save it? There are quite a number of tools to convert XML files in to other formats, I believe.

goetz · wrote on 5 Dec 2010, 21:31

You did read of that "platform independent" thingy, didn't you? :) To be able to work on a Mac I cannot use the Microsoft tools. And of course that tool exists, it's called Excel :)

xsacha · wrote on 5 Dec 2010, 21:46

I think it's a downloadable tool for people with old versions of Excel actually. Standalone. But yes, it was a Windows app.

You have Excel on "Mac":http://www.ehow.co.uk/how_6316841_convert-xls-xlsx-mac.html too :P

There may be a Mac app for this. Or you could try wine (or similar).

Probably make life much easier.

goetz · wrote on 5 Dec 2010, 21:49

Come on... you cannot force your commercial customers to install wine just to convert some crappy xls files :-)

Everthing other than a lib I can incorporate to my app is not acceptable; it's more pleasent for the user if we upload the files to the business logic server then.

xsacha · wrote on 5 Dec 2010, 21:55

Alright, I guess since it is for paying customers it is best to treat them nice.

Good luck with your Excel API. I'm sure someone has written something like it for Qt somewhere. You checked Qt-Apps already and similar sites?

This can search Excel files: http://qt-apps.org/content/show.php/recoll?content=66138
But might not have the full API.

goetz · wrote on 5 Dec 2010, 22:00

I've searched around with google, got some things that might be interesting, but nothing with using Qt in the first search results. It's not on a very high priority at the moment, so no need to worry. I thought it's worth a try in this forum - if you don't ask, you won't get an answer...

Yash · wrote on 28 Dec 2010, 12:33

There are 2 C++ libaries to create excel.
One is free xlslib : http://xlslib.sourceforge.net/
Other is commercial libXL : http://www.libxl.com/

Sorry for late response and I don't know whether you need this or not. But for others I share...

goetz · wrote on 28 Dec 2010, 13:02

Thanks for the links. libxl I will have a look into. xlslib unfortunately cannot read XLS files. This is the crucial part. Writing the files could be quite easily approached with the new XML based format (thats seems not too complicated as long as there are no formulas or cross references, which we do not need).

qtrahul · wrote on 28 Dec 2010, 14:10

Another available option is to attempt to extract the code from an open source excel reading competitor.

Open Office - http://www.openoffice.org/ - is likely to be used,

Gnumeric is probably a better option.
Excel code is here - http://git.gnome.org/browse/gnumeric/tree/plugins/excel

Yash · wrote on 29 Dec 2010, 04:42

Libxls
libxls is a C library which can read Excel (xls) files. It has been tested on Linux x86 and Cygwin but may work on any little-endian system. ...
"libxls.sourceforge.net":http://libxls.sourceforge.net

[EDIT: clickable link, Volker]

goetz · wrote on 29 Dec 2010, 13:31

Thanks for the link Yash, it looks promising. It could be a good start and maybe I find some time to make a Qt version.

Panke · wrote on 5 Jan 2011, 22:45

What's about KOffice? As far as I know they use MS -> OOo -> KOffice, but they might have a cuter API to the OOo routines since they are Qt-based.

goetz · wrote on 5 Jan 2011, 23:16

KOffice falls out due to license issues - unfortunately.

fcrochik · wrote on 5 Jan 2011, 23:53

[quote author="Yash" date="1293597766"]Libxls
[EDIT: clickable link, Volker][/quote]
Not yet....

"libxls.sourceforge.net":http://libxls.sourceforge.net

goetz · wrote on 5 Jan 2011, 23:55

Thanks - corrected * 2 :-)