void bgnplot (monitor, screentype, filename) BPLT.C Level 0
Schar monitor = 1 if picture is to be plotted on the screen and stored in Tektronix format. 
= 0 if the picture is to be stored and not plotted. 
(Schar is defined as a signed char.)
Schar screentype = 't' if only text is to be displayed on the screen. 
The result of using a 't' is the same as using a 0 for the monitor argument. 
= 'g' if only graphics are to be displayed on the screen. The result of using a 'g' is the same as using a 1 for the monitor argument. The apostrophes around the characters are required.
char *filename The name given to the output Tektronix-format metafile. It must be enclosed in double quotes, and you must be sure to specify the correct drive. If you want to suppress the TKF file, use the name notek. If you are creating a series of plots you can use the function NewFile() to prevent the TKF file from becoming too long or to save each plot in a separate file. If you use NewFile() with the same file name each time, only the last picture will be saved to disk.
bgnplot() is the first call that you should make to GraphiC. It opens an output file with the extension .TKF to receive the Tektronix-formatted data, initializes the defaults for many parameters, and loads the video driver. A second file with the extension .OFF is created to keep track of the start and end locations of each plot in the TKF file. The .OFF file allows direct access to individual plots when they are replayed. Unless you want a series of plots, each with its own TKF file, bgnplot() should be called only once, at the beginning of the plotting session. All GraphiC sessions started with a call to bgnplot() must end with a call to stopplot(). If you desire several different metafiles, then several bgnplot()/stopplot() pairs may be employed, using a different file name in each call to bgnplot(). See stopplot()