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in C. Names (functions and variables) declared outside of a function block may be visible either only within a given translation unit, in which case they are said to have internal linkage – they are not visible to the linker – or may be visible to other object files, in which case they are said to
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C does not have a notion of modules. However, separate object files (and hence also the translation units used to produce object files) function similarly to separate modules, and if a source file does not include other source files, internal linkage (translation unit scope) may be thought of as
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is the most common even for C++), and generally do not contain function or variable definitions to avoid name conflicts when headers are included in multiple source files, as is often the case. Header files can be, and often are, included in other header files. It is standard practice for all
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based on a file, the actual source code fed into the compiler may appear substantially different than the source file that the programmer views, particularly due to the recursive inclusion of headers.
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This article is about the C and C++ programming term. For the meaning of the term in linguistics, see
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Note that the preprocessor is in principle language agnostic, and is a
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Input to a C or C++ compiler from which an object file is generated
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