java - Undefined reference to function with Cmake in Android studio -

i try add c functions java android app.
managed run basic function hello world in c.
in file hello.c call c function contained in file (astart.c) calls function c in file (util.c) calls others functions in others files.
no problem that, not it?

i add libraries cmakelists.txt :

# sets minimum version of cmake required build native # library. should either keep default value or pass # value of 3.4.0 or lower.  cmake_minimum_required(version 3.4.1)  # creates , names library, sets either static # or shared, , provides relative paths source code. # can define multiple libraries, , cmake builds you. # gradle automatically packages shared libraries apk.  add_library( # sets name of library.          native-lib           # sets library shared library.          shared           # provides relative path source file(s).          # associated headers in same location source          # file automatically included.          src/main/cpp/native-lib.cpp )  add_library( hello           # sets library shared library.          shared           src/main/mycpp/hello.c )  add_library( astart           # sets library shared library.         shared           src/main/mycpp/astart.c )  add_library( ai           # sets library shared library.          shared           src/main/mycpp/lib/ai.c )  add_library( sha           # sets library shared library.          shared           src/main/mycpp/lib/sha.c )  add_library( util           # sets library shared library.          shared           src/main/mycpp/lib/util.c )  add_library( allnet_log           # sets library shared library.          shared           src/main/mycpp/lib/allnet_log.c )  #add_library( packet           # sets library shared library. #            shared  #           src/main/mycpp/lib/packet.c )  add_library( configfiles           # sets library shared library.          shared           src/main/mycpp/lib/configfiles.c )  add_library( allnet_queue           # sets library shared library.          shared           src/main/mycpp/lib/allnet_queue.c )    # add directories cpp header files let cmake             find them during compile time include_directories(src/main/mycpp/) include_directories(src/main/mycpp/lib/)  # searches specified prebuilt library , stores path # variable. because system libraries included in search path # default, need specify name of public ndk library # want add. cmake verifies library exists before # completing build.  find_library( # sets name of path variable.           log-lib            # specifies name of ndk library           # want cmake locate.           log )  # specifies libraries cmake should link target library. # can link multiple libraries, such libraries define in # build script, prebuilt third-party libraries, or system libraries.  target_link_libraries( # specifies target library.                    native-lib                     # links target library log library                    # included in ndk.                    ${log-lib} ) 

my gradle file :

apply plugin: 'com.android.application'  android { compilesdkversion 25 buildtoolsversion "25.0.0" defaultconfig {     applicationid "com.example.hippolytelacassagne.allnet"     minsdkversion 19     targetsdkversion 25     versioncode 1     versionname "1.0"     testinstrumentationrunner    "android.support.test.runner.androidjunitrunner"     externalnativebuild {         cmake {             cppflags ""             cflags "-fexceptions"         }     } } buildtypes {     release {         minifyenabled false         proguardfiles getdefaultproguardfile('proguard-android.txt'), 'proguard-rules.pro'     } } externalnativebuild {     cmake {         path "cmakelists.txt"     } }  // if want gradle package prebuilt native libraries // apk, modify default source set configuration // include directory of prebuilt .so files follows. sourcesets {     main {         jni.srcdirs = []         jnilibs.srcdirs 'imported-lib/src/', 'more-imported-   libs/src/'     } } }  dependencies { compile filetree(include: ['*.jar'], dir: 'libs') androidtestcompile('com.android.support.test.espresso:espresso-core:2.2.2', {     exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.3.1' testcompile 'junit:junit:4.12' } 

my hello.c called in home.java :

#include <jni.h>  #include "lib/app_util.h" #include "lib/packet.h" #include "astart.c"  jniexport jstring jnicall java_com_example_hippolytelacassagne_allnet_home_hello( jnienv *env, jobject callingobject) {     char * args [] = { "allnet", "-v", "def", null };     astart_main(3, args);     return (*env)->newstringutf(env, "hello world"); } 

the includes if astart.c called in hello.c :

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <fcntl.h> #include <signal.h> #include <pwd.h> #include <ifaddrs.h> #include <dirent.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/wait.h> #include <sys/socket.h> #include <netinet/in.h> #include <net/if.h>      /* iff_loopback, etc */ #include <arpa/inet.h>   /* inet_addr */  #include "lib/util.h" #include "lib/allnet_log.h" #include "lib/packet.h" #include "lib/configfiles.h" #include "lib/allnet_queue.h" 

and includes of util.c called in astart.c :

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <fcntl.h> #include <time.h> #include <assert.h> #include <errno.h> #include <netdb.h>  /* h_errno */ #include <dirent.h>  /* h_errno */ #include <sys/time.h> #include <sys/stat.h> #include <sys/socket.h> #include <sys/types.h> #include <sys/un.h> #include <netinet/in.h> #include <arpa/inet.h>  #include "packet.h" #include "mgmt.h" #include "allnet_log.h" #include "util.h" #include "ai.h" #include "sha.h" 

and here error message of gradle console :

    failure: build failed exception.  * went wrong: execution failed task ':app:externalnativebuilddebug'. > build command failed.   error while executing '/users/hippolytelacassagne/library/android/sdk/cmake/3.6.4111459/bin/cmake' arguments {--build /users/hippolytelacassagne/androidstudioprojects/allnet/app/.externalnativebuild/cmake/debug/mips64 --target util}   [1/2] building c object cmakefiles/util.dir/src/main/mycpp/lib/util.c.o   [2/2] linking c shared library ../../../../build/intermediates/cmake/debug/obj/mips64/libutil.so   failed: : && /users/hippolytelacassagne/library/android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang  --target=mips64el-none-linux-android --gcc-toolchain=/users/hippolytelacassagne/library/android/sdk/ndk-bundle/toolchains/mips64el-linux-android-4.9/prebuilt/darwin-x86_64 --sysroot=/users/hippolytelacassagne/library/android/sdk/ndk-bundle/sysroot -fpic -isystem /users/hippolytelacassagne/library/android/sdk/ndk-bundle/sysroot/usr/include/mips64el-linux-android -d__android_api__=21 -g -dandroid -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -fintegrated-as -wa,--noexecstack -wformat -werror=format-security -fexceptions -o0 -fno-limit-debug-info  -wl,--exclude-libs,libgcc.a --sysroot /users/hippolytelacassagne/library/android/sdk/ndk-bundle/platforms/android-21/arch-mips64 -wl,--build-id -wl,--warn-shared-textrel -wl,--fatal-warnings -wl,--no-undefined -wl,-z,noexecstack -qunused-arguments -wl,-z,relro -wl,-z,now -shared -wl,-soname,libutil.so -o ../../../../build/intermediates/cmake/debug/obj/mips64/libutil.so cmakefiles/util.dir/src/main/mycpp/lib/util.c.o  -lm && :   cmakefiles/util.dir/src/main/mycpp/lib/util.c.o: in function `mgmt_to_string':   /users/hippolytelacassagne/androidstudioprojects/allnet/app/src/main/mycpp/lib/util.c:245: undefined reference `ia_to_string'   /users/hippolytelacassagne/androidstudioprojects/allnet/app/src/main/mycpp/lib/util.c:274: undefined reference `ia_to_string'   cmakefiles/util.dir/src/main/mycpp/lib/util.c.o: in function `init_packet':   /users/hippolytelacassagne/androidstudioprojects/allnet/app/src/main/mycpp/lib/util.c:532: undefined reference `sha512_bytes'   cmakefiles/util.dir/src/main/mycpp/lib/util.c.o: in function `print_gethostbyname_error':   /users/hippolytelacassagne/androidstudioprojects/allnet/app/src/main/mycpp/lib/util.c:1554: undefined reference `log_print'   clang: error: linker command failed exit code 1 (use -v see invocation)   ninja: build stopped: subcommand failed.   * try: run --stacktrace option stack trace. run --info or --debug option more log output.  build failed 

it appear errors come functions of util.c.
don't understand because functions supposedly not defined defined in included files.

does have idea? thank you.

i found problem.
android studio needs specify dependencies between files in cmakelists :

target_link_libraries( # specifies target library.                    util                    sha                    ai                    allnet_log                     # links target library log library                    # included in ndk.                    ${log-lib} ) 

the #includes in file not enough.