ICTERM is essentially equivalent to CTERM but can return the user response to the calling program.
Note: as in CTERM(2), the user will be prompted for a "clear screen" when a call to ICTERM(2) is made. However, additional user options are available including "X" for exit to user program and "<control>Z" or EOF. Other replies include "Y" for yes, "N" for no (the default), "Q" (quit), "S" (skip one), "P" (pass many), or "D" (dump). "Y" and "N" clear the screen as indicated and the program continues normally. A reply of "Q" permanently disables terminal screen plotting until the package is reinitialized by FRAME. A replot of "S" disables screen plotting until the next CTERM(2) or ICTERM(2) call whereupon the "clear screen" prompt reappears as before. A reply of "P" is similar to "S", but the user will be prompted for the number of CTERM(2) or ICTERM\(2) calls to pass before reissuing the prompt. In this manner multiple terminal screen "pages" can be skipped. A reply of "D" will enable a dump of the screen to the attached terminal printer (if supported on the particular terminal/printer). Note that during a skip that any changes of origin by PLOT, scale factors by FACTOR or VFACTOR, or pen color or linetype will NOT take place.
iret = ICTERM (iarg)
iarg (I): terminal operation code
= 0 : initialize graphics mode on terminal
= 1 : return terminal from graphics to text mode
=-1 : return terminal text to graphics mode
= 2 : return terminal to text mode, and prompt
user for clear screen (see note above)
=-2 : return terminal to text mode, clear graphics screen
= 3 : clear text screen, leave in text mode
=-3 : clear graphics screen, leave in terminal mode
= 4 : dump graphics screen to printer
=-4 : clear text, graphics, leave in graphics mode
= 5 : turn off graphics screen, return to text mode
=-5 : turn on graphics screen, return to graphics mode
= 6 : toggle reverse video
= 8 : de-initialize graphics terminal
iret (I): (returned) user option code
= 0 : normal user response (Y,N,S, etc.)
= 1 : user exit (X) response
=-1 : EOF or "^Z" response