SetEnviron

Sets a system environment variable

Syntax
   Declare Function SetEnviron ( ByRef varexpression As String ) As Long

Usage
   result = SetEnviron( varexpression )

Parameters
   varexpression
      Name and setting of an environment variable in the following (or 
      equivalent) form: varname=varstring.
      (varname being the name of the environment variable, and varstring 
      being its text value to set)

Return Value
   Return zero (0) if successful, non-zero otherwise.

Description
   Modifies system environment variables.  There are several variables 
   available for editing other than the default ones on your system.  An 
   example of this would be fbgfx, where you can choose the form of 
   graphics driver the FreeBASIC graphics library will use.

Example
   'e.g. to set the system variable "path" to "c:":

   Shell "set path" 'shows the value of path
   SetEnviron "path=c:"
   Shell "set path" 'shows the new value of path

     '' WINDOWS ONLY EXAMPLE! - We just set the graphics method to use
     '' GDI rather than DirectX (or Direct2D added on new systems).
     '' You may note a difference in FPS.
   SetEnviron("fbgfx=GDI")

     '' Desktop width/height
   Dim As Long ScrW, ScrH, BPP
   ScreenInfo ScrW, ScrH, BPP

     '' Create a screen at the half width/height of your monitor.
     '' Normally this would be slow, but GDI is fairly fast for this kind
     '' of thing.
   ScreenRes ScrW/2, ScrH/2, BPP

     '' Start our timer/
   Dim As Double T = Timer

     '' Lock our page
   ScreenLock
   Do
     
      '' Print time since last frame
     Locate 1, 1
     Print "FPS: " & 1 / ( Timer - T )
     T = Timer
     
      '' Flip our screen
     ScreenUnlock
     ScreenLock
      '' Commit a graphical change to our screen.
     Cls
     
   Loop Until Len(Inkey)

     '' unlock our page.
   ScreenUnlock

Platform Differences
   * In Linux, varexpression  must be permanent (a literal, a variable 
     declared in the main code or a static variable declared in a 
     procedure), because Linux does not memorize the string but only a 
     pointer to its data characters.

Differences from QB
   * In QB, SetEnviron was called Environ.

See also
   * Environ
   * Shell

