man vline () - Draws a vertical line onto the bitmap. Allegro game programming library.
NAME
vline - Draws a vertical line onto the bitmap. Allegro game programming library.
SYNOPSIS
#include <allegro.h>
void vline(BITMAP *bmp, int x, int y1, int y2, int color);
DESCRIPTION
Draws a vertical line onto the bitmap, from point (x, y1) to (x, y2).
Note: vline() is implemented as an alias to another function. See ALLEGRO_NO_VHLINE_ALIAS in the `Differences between platforms' section for details.