[Plplot-devel] [BUG] problem with dynamic drivers and multiple precision libs

[Maurice L. <mj...@ga...>]

I recently ran into the following gotcha.  I had an application that ran just
fine in double precision, but after installing a new version of plplot with
float precision, it broke.  The reason: only one precision of dynamic drivers
is built, and they're potentially being used in conjunction with both
precision libraries.  This is a real recipe for trouble.

My immediate problem looks to occur in plbuf_swin, which I will fix.  I'm also
worried about any driver call to or from the plplot library that involves
PLFLT's.  Fortunately, there's not too many.  For example, every driver
calls plP_setpxl which passes PLFLT's on the stack.  Since ANSI C is not
supposed to auto promote to double, this could be trouble.

A possible solution is:
 - drivers may only call internal plplot functions
 - those functions callable by drivers that use PLFLT's in the argument list
be changed to use double instead.

-- 
Maurice LeBrun    mj...@ga...