In computer science, compile time refers to either the operations performed by a compiler (the "compile-time operations"), programming language requirements that must be met by source code for it to be successfully compiled (the "compile-time requirements"), or properties of the program that can be reasoned about at compile time.
The operations performed at compile time usually include syntax analysis, various kinds of semantic analysis (e.g., type checks and instantiation of template) and code generation.
Programming language definitions usually specify compile time requirements that source code must meet to be successfully compiled. For example, that the amount of storage required by types and variable can be deduced.
Properties of a program that can be reasoned about at compile time include range-checks (e.g., proving that an array index will not exceed the array bound), deadlock freedom in concurrent languages, or timings (e.g., proving that a sequence of code takes no more than an allocated amount of time).
Compile time occurs before link time (when the output of one or more compiled files are joined together) and runtime (when a program is executed). In some programming languages it may be necessary for some compilation and linking to occur at runtime. There is a trade-off between compile-time and link-time in that many compile time operations can be deferred to link-time without incurring extra run-time.
"Compile time" can also refer to the amount of time required for compilation.
Famous quotes containing the words compile and/or time:
“If I were a maker of books I should compile a register, with comments, of different deaths. He who should teach people to die, would teach them to live.”
—Michel de Montaigne (1533–1592)
“The true charm of pedestrianism does not lie in the walking, or in the scenery, but in the talking. The walking is good to time the movement of the tongue by, and to keep the blood and the brain stirred up and active; the scenery and the woodsy smells are good to bear in upon a man an unconscious and unobtrusive charm and solace to eye and soul and sense; but the supreme pleasure comes from the talk.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)