An error occurs that the defined function is not defined during the Android ndk build.

Please help me to get an error in the "process(input, output)" of the code below during the ndk-build operation.

[audacity_process.cpp]

#include <jni.h>
#include <string.h>
#include "noisereduction/Audacity.h"
#include <stdio.h>

#include <android/log.h>

JNIEXPORT void JNICALL Java_com_example_gonghoonnt_audacity_Audacity_preprocess(JNIEnv* env, jobject, jstring inputPath, jstring outputPath)
{
    const char * input = (env)->GetStringUTFChars(inputPath, 0);
    const char * output = (env)->GetStringUTFChars(outputPath, 0);

    process(input, output); // Error occurred

    return;
}

[ERROR]

jni/audacity_process.cpp:13: error: undefined reference to 'process(char const*, char const*)'
clang++.exe: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [obj/local/armeabi-v7a/libnoisereduction.so] Error 1

[Audacity.h]

void process (const char* inputPath; const char* outputPath);

[Audacity.cpp]

#include <iostream>
#include "NoiseReduction.h"
#include <sndfile.h>
#include "loguru.hpp"
#include "Utils.h"
#include "cxxopts.hpp"
#include "Audacity.h"

void process(const char* inputPath, const char* outputPath) {
    auto ctx = openAudioFile(inputPath);

    NoiseReduction::Settings settings;
    NoiseReduction reduction(settings, ctx);
    auto t0 = 0;
    auto t1 = ctx.info.frames;

    reduction.ProfileNoise(t0, t1);
    reduction.ReduceNoise(outputPath);

    return 0;
}

I made it as above, but I don't know what to do because there is an error that says it's not defined.

In addition, android.mk and application.mk are organized as follows:

LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := noisereduction

LOCAL_CFLAGS = -DFIXED_POINT -DUSE_KISS_FFT -DEXPORT="" -UHAVE_CONFIG_H

LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

FILES := audacity_process.cpp

LOCAL_SRC_FILES := $(FILES)

LOCAL_LDLIBS :=  -llog

include $(BUILD_SHARED_LIBRARY)