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Creating C language targets

Include C language code as a target in your Swift package.

Overview

C language targets are structured similarly to Swift targets, with the additional of a directory, commonly named include, to hold public header files. If you use a directory other than include for public headers, declare it using the publicHeadersPath parameter on target.

Swift Package manager allows only one valid C language main file for executable targets. For example, it is invalid to have main.c and main.cpp in the same target.

Exposing C functions to Swift

Swift Package Manager automatically generates a module map for each C language library target for these use cases:

  • If include/Foo/Foo.h exists, Foo is the only directory under the include directory, and the include directory contains no header files, then Swift package manager uses include/Foo/Foo.h as the umbrella header.

  • If include/Foo.h exists and include contains no other subdirectory, then Swift package manager uses include/Foo.h as the umbrella header for the module map.

  • Otherwise, Swift package manager uses the include directory as an umbrella directory; all headers under it are included in the module.

In case of complicated include layouts or headers that are not compatible with modules, provide a module.modulemap in the include directory.

See Also

Guides