=====Pausing under program control=====

//by Richard Russell, February 2007//\\ \\  When running a program from the Interactive Development Environment you can enter (or exit) **paused** mode using the menu selection **Run... Pause**, clicking the **Pause** button on the toolbar or pressing the **F8** key (if the IDE window has the input focus).\\ \\  It is also possible to enter and exit **paused** mode automatically using statements within your own BASIC program. To enter paused mode execute the following code:\\ \\ 
<code bb4w>
        TRACE STEP ON
</code>
As soon as this statement is executed the program will pause and can be single-stepped in the usual way (via a menu selection, the Step button in the toolbar or pressing F7). You will normally want to select the **Trace** and/or **List Variables** utility to display useful information while stepping.\\ \\  To exit paused mode and resume normal execution use the following code:\\ \\ 
<code bb4w>
        TRACE STEP OFF
</code>
You may wish to write your own **PROCpause** and **PROCunpause** procedures which execute these statements conditionally depending on some detected state. For example to pause only when the program is running under the IDE you can do:\\ \\ 
<code bb4w>
        DEF PROCpause
        LOCAL cmd%
        SYS "GetCommandLine" TO cmd%
        IF INSTR($$cmd%, "bbcwin.exe") TRACE STEP ON
        ENDPROC
</code>
If you have a particularly difficult bug to trace you could arrange to pause your program only when a specific condition is met, such as a variable having a certain value or a particular key being pressed.