X Toolkit Intrinsics — C Language Interface is intended to be read by both application programmers who will use one or more of the many widget sets built with the Intrinsics and by widget programmers who will use the Intrinsics to build widgets for one of the widget sets. Not all the information in this manual, however, applies to both audiences. That is, because the application programmer is likely to use only a number of the Intrinsics functions in writing an application and because the widget programmer is likely to use many more, if not all, of the Intrinsics functions in building a widget, an attempt has been made to highlight those areas of information that are deemed to be of special interest for the application programmer. (It is assumed the widget programmer will have to be familiar with all the information.) Therefore, all entries in the table of contents that are printed in bold indicate the information that should be of special interest to an application programmer. It is also assumed that, as application programmers become more familiar with the concepts discussed in this manual, they will find it more convenient to implement portions of their applications as special-purpose or custom widgets. It is possible, nonetheless, to use widgets without knowing how to build them. Conventions Used in this Manual This document uses the following conventions: Global symbols are printed in this special font. These can be either function names, symbols defined in include files, data types, or structure names. Arguments to functions, procedures, or macros are printed in italics. Each function is introduced by a general discussion that distinguishes it from other functions. The function declaration itself follows, and each argument is specifically explained. General discussion of the function, if any is required, follows the arguments. To eliminate any ambiguity between those arguments that you pass and those that a function returns to you, the explanations for all arguments that you pass start with the word specifies or, in the case of multiple arguments, the word specify. The explanations for all arguments that are returned to you start with the word returns or, in the case of multiple arguments, the word return.