You can get information about language keywords, library functions, variables, constants, and error messages by placing the insertion point on the item and pressing F1. Help searches for information about the word and displays a help topic if available.
·To get information about the C run-time function acos:
1.Type acos in the source window.
2.Position the insertion point on acos and click.
3.Press F1. The Help window displays information about the function (see Figure 6.6).
In run-time library help, a series of buttons at the top of the help screen provides related information about the current topic.
| Button | Information Provided |
| Summary | Correct syntactical use of the language element in a program. |
| Description | Details about the language routine. |
| Example | Sample program using the language keyword or routine. The sample program can be copied and pasted into the source window. |
Figure 6.7 shows the information buttons.
To get information about error messages in the Errors window, move the insertion point to the error and press F1.