undefined reference to `icu_56::UnicodeString::UnicodeString(signed char, unsigned short const*, int)'
<p>I am running ubuntu, and I can build ICU </p>

<p>I have included:</p>

<pre><code>#include &lt;unistr.h&gt;
using namespace icu;
</code></pre>

<p>This is my build method for ICU:</p>

<pre><code>CPPFLAGS="-DU_USING_ICU_NAMESPACE=0" 
CPPFLAGS="-DU_CHARSET_IS_UTF8=1"

export CFLAGS="-DU_CHARSET_IS_UTF8=1 -DU_GNUC_UTF16_STRING=1 -DU_STATIC_IMPLEMENTATION"
export CXXFLAGS="-DU_USING_ICU_NAMESPACE=0 -std=gnu++0x -DU_CHARSET_IS_UTF8=1 -DU_GNUC_UTF16_STRING=1 -DU_HAVE_CHAR16_T=1 -DUCHAR_TYPE=char16_t -Wall --std=c++0x -DU_STATIC_IMPLEMENTATION"
export CPPFLAGS="-DU_USING_ICU_NAMESPACE=0 -DU_CHARSET_IS_UTF8=1 -DU_STATIC_IMPLEMENTATION"
export LDFLAGS="-std=gnu++0x"

./runConfigureICU Linux --enable-static --disable-shared --disable-renaming

make check 
sudo make install
</code></pre>

<p>I then link to</p>

<pre><code>/usr/local/lib/libicuuc.a
</code></pre>

<p>and try to compile</p>

<pre><code>icu::UnicodeString s1=UNICODE_STRING("such characters are safe 123 %-.", 32);
</code></pre>

<p>but get the error</p>

<pre><code>undefined reference to `icu_56::UnicodeString::UnicodeString(signed char, unsigned short const*, int)'
</code></pre>

<p>I found another post here on SO regarding the same problem, but when I follow the steps provided it does not fix my problem and may be a different version.</p>

<p>EDIT: This is the output from the IDE upon building the project</p>

<pre><code>Cleaning Solution: myProject (Debug)

Cleaning: myProject (Debug)
Removing output files...
Clean complete

Building Solution: myProject (Debug)

Building: myProject (Debug)
Performing main compilation...

Precompiling headers

    Compiling source to object files
    g++  -MMD "/home/user/myProject/myProject/main.cpp" -g -O0 -std=c++11 -DDEBUG -I"/home/user/myProject/myProject/include" -I"/home/user/myProject/icu/unicode" -I"/home/user/myProject/myProject/.prec/Debug"  -c -o "/home/user/myProject/myProject/bin/Debug/main.o"

    Generating binary "myProject" from object files
    g++ -o "/home/user/myProject/myProject/bin/Debug/myProject" "/home/user/myProject/myProject/bin/Debug/main.o"
"/home/user/myProject/icu/libicuuc.a" 
    /home/user/myProject/myProject/bin/Debug/main.o: In function `icuTest':
    /home/user/myProject/myProject/icuTest.hpp:3: undefined reference to `icu_56::StringPiece::StringPiece(char const*)'
    /home/user/myProject/myProject/icuTest.hpp:3: undefined reference to `icu_56::UnicodeString::fromUTF8(icu_56::StringPiece const&amp;)'
    /home/user/myProject/myProject/icuTest.hpp:3: undefined reference to `icu_56::UnicodeString::~UnicodeString()'
    /home/user/myProject/myProject/icuTest.hpp:3: undefined reference to `icu_56::UnicodeString::~UnicodeString()'
    collect2: error: ld returned 1 exit status
    Build complete -- 4 errors, 0 warnings

    ---------------------- Done ----------------------

    Build: 4 errors, 0 warnings
</code></pre>