Stepping Through a Program

You must begin execution by choosing Run or Run (args) (or issuing run from the command line). If execution stops before the program finishes (for example, because you have set a breakpoint), you can then step through the program, as described in this section. To step through the entire program, set a breakpoint at the first executable line, and then run to it. (See " Setting Breakpoints" for information on setting breakpoints.)

From the menu bar:

• Choose the Step selection from the Execute menu to execute the next line of the program. (It is by default in the tear-off region.) Step steps into any functions called on that line.

• Choose the Next selection from the Execute menu to execute the next statement of the program. (It is also by default in the tear-off region.) Next steps over any function called in the line, considering the function to be a single statement.

• Choose the Stepout selection from the Execute menu to execute the current function, then return to its caller.

The execution pointer moves to indicate the next line to be executed.

From the command window:

• Issue the step, next, or stepout command from the command line to perform the same action as the equivalent menu-bar selection; return is a synonym for stepout. In addition, you can specify the number of lines to be executed as an argument to step and next, and you can specify as an argument to stepout the number of levels of the call stack that you want to step out.

• The stepi and nexti commands are also available for stepping by machine instruction. The address and instruction are displayed in the command window.

If execution takes considerable time--for example, because Next calls a long-running function--the status changes to running. You can use Prism, but many commands will be unavailable. Unavailable selections are grayed out in menus.