NodeJS: node-gyp compile with the equivalent gcc -lm option - c++

Question

I'm new in developing nodejs addons in C++.
I have a static c lib that I include in my addon, the lib is needed to talk to a custom hardware, but some functions of this library uses math.h. So when I compile in a C example I do: gcc main.c libmackrnp6_0_2_fPIC.a -o test -lm, no problem there, but when I include this lib in the cpp addon I have a problem with the pow function.
How can I compile the addon sudo node-gyp configure build with the -lm option (gcc equivalent)?
binding.gyp
{
"targets": [
{
"target_name": "octotuner",
"sources": [
"params.cpp",
"headerv6.h"
],
"libraries": ["/home/nvidia/webrf/api/libmackrnp6_0_2_fPIC.a"],
"link_settings": {
"libraries": [
"-lm"
]
},
}
]
}
params.cpp
#include <node.h>
#include <iostream>
#include <stdio.h>
extern "C" {
#include "headerV6.h"
}
using namespace v8;
using namespace std;
void getParams(const FunctionCallbackInfo<Value>& args) {
Isolate* isolate = args.GetIsolate();
int status = 0, numplaca = 0;
unsigned char json[9999] = ""; //<-- the lib function needs this (I know)
unsigned char flagTuner = 0;
int timeOut = 20; //segundos
parametros(json, flagTuner, numplaca, timeOut, &status); // <-- this uses pow
std::string sJson(reinterpret_cast<char*>(json));
Local<String> retval = String::NewFromUtf8(isolate, sJson.c_str());
args.GetReturnValue().Set(retval);
}
void Initialize(Local<Object> exports) {
NODE_SET_METHOD(exports, "getRF", getParams);
}
NODE_MODULE(octotuner, Initialize);
teste.js
const rf = require('./build/Release/octotuner');
console.log(rf.getRF())
Testing
sudo node teste.js
Output:
{
"Numero_da_Placa":0,
"Comando_OK":1,
"Tuner0":{
"Canal_Fisico":25,
"QUALIDADE_LA":"-",
"QUALIDADE_LB":"-",
"QUALIDADE_LC":"-",
"BER_LA":"-",
"BER_LB":"-",
"BER_LC":"-",
"Potencia":-1.95,
"SNR":3.9,
"Modo":"8K",
"Intervalo_de_Guarda":"1/8",
"Modulacao_LA":"QPSK",
"Taxa_do_Codigo_LA":"2/3",
"Entrelacamento_LA":400,
"Segmentos_LA":1,
"Modulacao_LB":"64-QAM",
"Taxa_do_Codigo_LB":"3/4",
"Entrelacamento_LB":200,
"Segmentos_LB":3,
"Modulacao_LC":"Error",
"Taxa_do_Codigo_LC":"Error",
"Entrelacamento_LC":"Error",
"Segmentos_LC":"Error"
}
}
C program that uses the same library (not in addon, just for testing):
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "headerV6.h"
int main(int argc, char *argv[]){
int i = 0, status = 0, numplaca = 0;
char json[9999] = {0};
unsigned char flagTuner = 0;
int timeOut = 20; //segundos
parametros(json, flagTuner, numplaca, timeOut, &status);
printf("%s", json);
return 0;
}
Compiled with: gcc params.c libmackrnp6_0_2_fPIC.a -o teste
Compile FAIL (that's why I think the problem with the addon is that it's not linking math lib)
(metadados.o): na função `recoverDataNum':
metadados.c:(.text+0x138): referência indefinida para `pow'
metadados.c:(.text+0x1d8): referência indefinida para `pow'
collect2: error: ld returned 1 exit status
Compiled with: gcc params.c libmackrnp6_0_2_fPIC.a -o teste -lm
Compile OK
Testing:
sudo ./teste
{
"Numero_da_Placa":0,
"Comando_OK":1,
"Tuner0":{
"Canal_Fisico":25,
"QUALIDADE_LA":100.0,
"QUALIDADE_LB":100.0,
"QUALIDADE_LC":"-",
"BER_LA":0.0000e+00,
"BER_LB":0.0000e+00,
"BER_LC":"-",
"Potencia":-19.50,
"SNR":37.9,
"Modo":"8K",
"Intervalo_de_Guarda":"1/8",
"Modulacao_LA":"QPSK",
"Taxa_do_Codigo_LA":"2/3",
"Entrelacamento_LA":400,
"Segmentos_LA":1,
"Modulacao_LB":"64-QAM",
"Taxa_do_Codigo_LB":"3/4",
"Entrelacamento_LB":200,
"Segmentos_LB":12,
"Modulacao_LC":"-",
"Taxa_do_Codigo_LC":"-",
"Entrelacamento_LC":"-",
"Segmentos_LC":"-"
}
}

Answer 1

Solved
I've used the following binding.gyp and I've got a new version of the thirdy part library and it's working now! Thanks.
{
"targets": [
{
"target_name": "octotuner",
"sources": [
"params.cpp"
],
"include_dirs": [
"./so"
],
"link_settings": {
"libraries": ["/home/nvidia/webrf/api/so/libmackrnp6_0_2_fPIC.a","-lm"],
}
}
]
}