Link libmpich to android NDK

Issue

I have generated Uclib using buildroot and used it to compile mpich for ARM devices.Then I created Android project and copied libmpich.a and the Include folder to the project here is the Android.mk:

LOCAL_PATH := $(call my-dir)
# static library info

LOCAL_MODULE_FILENAME:= libmpich
LOCAL_MODULE := libmpich
LOCAL_SRC_FILES := ../prebuilt/libmpich.a 
LOCAL_EXPORT_C_INCLUDES := ../prebuilt/include
LOCAL_STATIC_LIBRARIES := libmpich
include $(PREBUILT_STATIC_LIBRARY)

# wrapper info
include $(CLEAR_VARS)

LOCAL_C_INCLUDES += ../prebuilt/include
LOCAL_MODULE    := ndk1
LOCAL_SRC_FILES := native.c
LOCAL_STATIC_LIBRARIES := libmpich
include $(BUILD_SHARED_LIBRARY)

after ndk-build i got the following error

jni/../prebuilt/libmpich.a(initthread.o):initthread.c:function PMPI_Init_thread: error: undefined reference to 'MPL_env2bool'
jni/../prebuilt/libmpich.a(msgprint.o):msgprint.c:function MPIU_Usage_printf: error: undefined reference to 'stdout'
jni/../prebuilt/libmpich.a(msgprint.o):msgprint.c:function MPIU_Error_printf: error: undefined reference to 'stderr'
jni/../prebuilt/libmpich.a(msgprint.o):msgprint.c:function MPIU_Internal_error_printf: error: undefined reference to 'stderr'
jni/../prebuilt/libmpich.a(msgprint.o):msgprint.c:function MPIU_Internal_sys_error_printf: error: undefined reference to 'stderr'
jni/../prebuilt/libmpich.a(msgprint.o):msgprint.c:function MPIU_Msg_printf: error: undefined reference to 'stdout'
jni/../prebuilt/libmpich.a(dbg_printf.o):dbg_printf.c:function MPIU_dbg_printf: error: undefined reference to 'stdout'
jni/../prebuilt/libmpich.a(dbg_printf.o):dbg_printf.c:function MPIU_dump_dbg_memlog_to_stdout: error: undefined reference to 'stdout'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2int'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2int'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2int'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2int'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2bool'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2bool'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2bool'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2str'
jni/../prebuilt/libmpich.a(param_vals.o):param_vals.c:function MPIR_Param_init_params: error: undefined reference to 'MPL_env2str'
jni/../prebuilt/libmpich.a(mpid_abort.o):mpid_abort.c:function MPID_Abort: error: undefined reference to 'stderr'
jni/../prebuilt/libmpich.a(mpid_vc.o):mpid_vc.c:function MPIDI_Populate_vc_node_ids: error: undefined reference to '__errno_location'
jni/../prebuilt/libmpich.a(mpid_vc.o):mpid_vc.c:function MPIDI_Populate_vc_node_ids: error: undefined reference to '__ctype_b'
jni/../prebuilt/libmpich.a(init.o):init.c:function PMPI_Init: error: undefined reference to 'MPL_env2str'
jni/../prebuilt/libmpich.a(strerror.o):strerror.c:function MPIU_Strerror: error: undefined reference to '__xpg_strerror_r'
jni/../prebuilt/libmpich.a(simple_pmi.o):simple_pmi.c:function accept_one_connection: error: undefined reference to '__errno_location'
jni/../prebuilt/libmpich.a(simple_pmi.o):simple_pmi.c:function PMI_Init: error: undefined reference to '__errno_location'
jni/../prebuilt/libmpich.a(sock.o):sock.c:function MPIDU_Socki_event_enqueue.isra.1: error: undefined reference to '__errno_location'
jni/../prebuilt/libmpich.a(sock.o):sock.c:function MPIDU_Sock_listen: error: undefined reference to 'MPL_env2range'
collect2: error: ld returned 1 exit status
make: *** [obj/local/armeabi/libndk1.so] Error 1

I don't understand why it is not linking correctly and what is missing

Update : when I add libmpl.a to the project all MPL errors disappeared

Solution

I think your problem occured because your static lib libmpich.a has dependance on another lib.

You have two diffenrent way to solve this issue :

1. Import any library needed by your libmpich.a as static library in your Android.mk as static library. The problem of this approach is that can be very long and painful if you have a lot dependance.

2. Build libmpich as a dynamic library, as dynamic library are package with their dependance. I do know how you build you libmpich library so i don't know if this will be hard to achieve. Once you have libmpich.so import it in your Android.mk as a dynamic library instead of a static one.

Answered By - sonic