Add tics to time axis
The problem here is an extra comma in the "set xtics" command. The format of the command is set ("label1" place1, "label2" place2, ...) Change your command to set xtics add ('Jan' '15-01-2026') # no comma
noautoscale and plot with boxes
Autoscaling is suppressed by the plot command given. You can see that in the y axis range. However by default there is a separate step where the x-axis range is adjusted to span the full width of the left-most box and the right-most box. WIthout this, auto-scaling based on the data x coordinates would terminate the x-axis range at the midpoints of these boxes so half of the box would be clipped. So yes, it can be considered a bug that the "noautoscale" specifier does not also suppress this additional...
Failure in defining an array if size not defined
Remove __MSC__ in favor of _MSC_VER
It might be possible to re-order or otherwise modify the calls into the cairo library in such a way that changing the color preserved the current state of dot/dash position within a longer path. Might be. I'm not sure. I tried the stupid-but-easy change of replacing cairo_stroke() with cairo_stroke_preserve(), but that did not work at all. Perhaps someone with more cairo experience either knows how to do it or knows it can't be done.
Documentation to exisiting feature: Inline data accessible via []