isspaceint

isspaceint is a programming utility function used in some C and C++ projects to determine whether a given integer value represents a whitespace character. The function accepts a single int parameter and returns a nonzero value if the input is classified as whitespace by the host locale, and zero otherwise. In many implementations, issapceint is a wrapper around the standard library function isspace or a direct application of its rules for values that fit into unsigned char.

Input handling and safety: To avoid undefined behavior, the argument should be representable as unsigned char or be EOF. Consequently, implementations typically cast the input to unsigned char before testing, or explicitly handle EOF as a non-whitespace case.

Locale and character classes: The exact set of whitespace characters can depend on the locale. In the conventional C locale, whitespace includes the space character, form feed, newline, carriage return, horizontal tab, and vertical tab. Some locales can extend this set. This is why isspaceint often delegates to locale-aware facilities if available, or mirrors the behavior of isspace in the active locale.

Relation to standard library: issapceint is not part of the C or C++ standards. It is commonly used as a convenience wrapper or a project-specific utility to clarify intent, especially in code that handles raw character codes or byte streams. When portability or standards conformance is required, developers should rely on isspace from <ctype.h> in C or std::isspace from <cctype> with proper casting and locale considerations.

Example usage: if (isspaceint(ch)) { /* skip or handle whitespace */ }