Variadic macro in the C preprocessorA variadic macro is a feature of some computer programming languages, especially the C preprocessor, whereby a macro may be declared to accept a varying number of arguments. Variable-argument macros were introduced in 1999 in the ISO/IEC 9899:1999 (C99) revision of the C language standard, and in 2011 in ISO/IEC 14882:2011 (C++11) revision of the C++ language standard. Support for variadic macros with no arguments was added in C++20 and will be added in C23.
Label (computer science)In programming languages, a label is a sequence of characters that identifies a location within source code. In most languages, labels take the form of an identifier, often followed by a punctuation character (e.g., a colon). In many high-level languages, the purpose of a label is to act as the destination of a GOTO statement. In assembly language, labels can be used anywhere an address can (for example, as the operand of a JMP or MOV instruction). Also in Pascal and its derived variations.
C preprocessorThe C preprocessor is the macro preprocessor for several computer programming languages, such as C, Objective-C, C++, and a variety of Fortran languages. The preprocessor provides inclusion of , macro expansions, conditional compilation, and line control. In many C implementations, it is a separate program invoked by the compiler as the first part of translation. The language of preprocessor directives is only weakly related to the grammar of C, and so is sometimes used to process other kinds of .
Function (computer programming)In computer programming, a function or subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed. Functions may be defined within programs, or separately in libraries that can be used by many programs. In different programming languages, a function may be called a routine, subprogram, subroutine, or procedure; in object-oriented programming (OOP), it may be called a method.
File descriptorIn Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a or other input/output resource, such as a pipe or network socket. File descriptors typically have non-negative integer values, with negative values being reserved to indicate "no value" or error conditions. File descriptors are a part of the POSIX API.