./speaks: error while loading shared libraries: libespeak-ng.so.1: cannot open shared object file: no such file or directory

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linker

C++14

I have downloaded the last version of `espeak-ng` from github, and did `./autogen.sh ./configure make make install`.
so I wrote a test program as you can see below:

#include <string.h>
    #include <vector> 
    #include </usr/local/include/espeak-ng/speak_lib.h>  
    
    int samplerate; // determined by espeak, will be in Hertz (Hz)
    const int buflength = 200; // passed to espeak, in milliseconds (ms)
    
    std::vector<short> sounddata;
    
    int SynthCallback(short *wav, int numsamples, espeak_EVENT *events) {
        if (wav == NULL)
            return 1; // NULL means done.
    
        /* process your samples here, let's just gather them */
        sounddata.insert(sounddata.end(), wav, wav + numsamples);
        return 0; // 0 continues synthesis, 1 aborts 
    }
    
    int main(int argc, char* argv[] ) {
        char text[] = {"my name is espeak"};
        samplerate = espeak_Initialize(AUDIO_OUTPUT_RETRIEVAL, buflength, NULL, 0);
        espeak_SetSynthCallback(&SynthCallback);
        espeak_SetVoiceByName("en"); 
        unsigned int flags=espeakCHARS_AUTO | espeakENDPAUSE;
        size_t size = strlen(text); 
        espeak_Synth(text, size + 1, 0, POS_CHARACTER, 0, flags, NULL, NULL); 
        espeak_Synchronize();
    

    
        return 0; 
    }

And compiled it by this command without any errors:

g++ -W -o speaks espeak.cpp -lespeak-ng

But when I try to run the executable by `./speaks` , I get this error message:

./speaks: error while loading shared libraries: libespeak-ng.so.1: cannot open shared object file: No such file or directory

What's the problem?

What I have tried:

I know `libespeak-ng.so.1` is here:

/usr/local/lib/libespeak-ng.so.1