Some features of C, its preprocessor, and/or implementation are inconsistently implementedinconsistent. One of C's features is three distinct classes of non-wide string literals. One is for run-time data, another is for include files with quotation marks around the filename, and the third is for include filenames in angle brackets. The allowed symbol set, and the interpretation of them, is not consistent between the three. To some extent this arose from the need to accommodate a wide variety of file naming conventions, such as [[MS-DOS]]'s use of backslash as a path separator.
Another consistency problem stems from shortcomings in C's preprocessor, which was originally implemented as a separate, relatively simple, process only loosely connected with the semantics of the rest of the language. The following code is legal Standard C:
