Linking static files generated in cmake

[Ujjwal21]

Hi @patrickgold ,

I used the script cc-icu4c.sh for building static ICU files for x86 platform. I am able to generate .a files.

I have linked these libraries with my target using cmake command target_link_libraries().

But when I am accessing some methods in <unicode/unistr.h> I am getting linking error saying undefined symbol.

Can you help me, if I am missing something.

[patrickgold]

Difficult to say, could you provide the exact linking error you receive?

My first guess though would be that you excluded a feature using the feature-flags that the method in unistr.h relies on, and now it got excluded.

[Ujjwal21]

Thanks @patrickgold,

Before giving you link error, here are other details -

1. I am on latest icu commit - bdcec144b9f627c8f96261a6afeebb52e4d81ab0 (Add four Japanese word into the dictionary). I simply cloned it and replaced the content of icu in your repo (Is this correct way to do?).

2. I am meeting all the requirements - 64 bit Linux, Android NDK r23, realpath installed (tested with $type -a realpath) command.

3. I changed cc-icu4c.sh to hardcode ndk_dir value to my local system path.

4. Executed - $ chmod +x cc-icu4c.sh
   $ ./cc-icu4c.sh build --arch=x86_64 --library-type=static

5. Linked the static libraries in my target using cmake command -
   target_include_directories(TARGET INTERFACE libicudata.a libicui18n.a libicuuc.a)

6. In code, I am including <unicode.unistr.h> and getting this linker error while calling UnicodeString constructor -
   ld: error: undefined symbol: icu_72::UnicodeString::UnicodeString(char const*)
   ld: error: undefined symbol: icu_72::UnicodeString::~UnicodeString()
   clang++: error: linker command failed with exit code 1

7. I ran nm libicuuc.a, and I could see 0000000000000000 T icu::UnicodeString::UnicodeString(char const*), so hopefully it is defined.

To your point, I didn't tweak any feature flag on my own. I simply used the script that in present in your code.

Also I just want "unicode" library, can you help me what will be correct parameters for your script, to reduce size of .a files

P.S. - We might need to change some flags as well for UnicodeString - https://github.com/unicode-org/icu/blob/47824c5568f0a1528c44e5264cb65e9e18705c18/docs/userguide/icu4c/build.md