where source-intro-stringseparates for the user's benefit the reference from the text which precedes it, filename is the name of the source file, and line-numberis the line number within that file (the first line is line 1).

If GDB prints some information about where the frame is from (which library, which load segment, etc.; currently only done on the RS/6000), it is annotated with

^Z^Zframe-where information

Then, if source is to be actually displayed for this frame (for example, this is not true for output from the backtrace command), then a source annotation (see “Displaying source” (page 304)) is displayed. Unlike most annotations, this is output instead of the normal text which would be output, not in addition.

20.5 Displays

When GDB is told to display something using the display command, the results of the display are annotated:

^Z^Zdisplay-begin number ^Z^Zdisplay-number-end number-separator^Z^Zdisplay-format format ^Z^Zdisplay-expression expression ^Z^Zdisplay-expression-end expression-separator^Z^Zdisplay-value

value ^Z^Zdisplay-end

where number is the number of the display, number-separatoris intended to separate the number from what follows for the user, format includes information such as the size, format, or other information about how the value is being displayed, expression is the expression being displayed, expression-separatoris intended to separate the expression from the text that follows for the user,and value is the actual value being displayed.

20.6 Annotation for GDB input

When GDB prompts for input, it annotates this fact so it is possible to know when to send output, when the output from a given command is over, etc.

Different kinds of input each have a different input type. Each input type has three annotations: a preannotation, which denotes the beginning of any prompt which is being output, a plain annotation, which denotes the end of the prompt, and then a post- annotation which denotes the end of any echo which may (or may not) be associated with the input. For example, the prompt input type features the following annotations:

20.5 Displays 301