Style 'linepoints' is not working.

[ghost]

Here is what i tried:

dimensions := 2
plot, _ := glot.NewPlot(dimensions, true, true)
fct := func(x float64) float64 { return math.Sin(x) }
groupName := "Sin Curve"
style := "linepoints"
var pointsX []float64
i := 0.0
for i < 50000{
    pointsX = append(pointsX, i/500)
    i += 1
}
plot.AddFunc2d(groupName, style, pointsX, fct)
plot.SavePlot("1.png")

The debug log showed nothing about style:

cmd> plot "/tmp/go-gnuplot-553750972" title "Sin Curve" with linepoints
res> 67
cmd> set terminal png
res> 17
cmd> set output'1.png'
res> 18
cmd> replot  
res> 9

But nothing happened, and the '1.png' is empty. did i do something wrong? thanks