5 Compiling and Linking C Extensions
A dynamic extension is a shared library (a.k.a. DLL) that extends PLT Scheme using the C API. An extension can be loaded explicitly via load-extension, or it can be loaded implicitly through require or load/use-compiled in place of a source file when the extension is located at
| (build-path "compiled" "native" (system-library-subpath) |
| (path-add-suffix file (system-type 'so-suffix))) |
relative to file.
For information on writing extensions, see Inside: PLT Scheme C API.
Three mzc modes help for building extensions:
--cc : Runs the host system’s C compiler, automatically supplying flags to locate the PLT Scheme header files and to compile for inclusion in a shared library.
--ld : Runs the host system’s C linker, automatically supplying flags to locate and link to the PLT Scheme libraries and to generate a shared library.
--xform : Transforms C code that is written without explicit GC-cooperation hooks to cooperate with PLT Scheme’s 3m garbage collector; see Overview in Inside: PLT Scheme C API.
Compilation and linking build on the dynext/compile and dynext/link libraries. The following mzc flags correspond to setting or accessing parameters for those libraries: --tool, --compiler, --ccf, --ccf, --ccf-clear, --ccf-show, --linker, ++ldf, --ldf, --ldf-clear, --ldf-show, ++ldl, --ldl-show, ++cppf, ++cppf ++cppf-clear, and --cppf-show.
The --3m flag specifies that the extension is to be loaded into the 3m variant of PLT Scheme. The --cgc flag specifies that the extension is to be used with the CGC. The default depends on mzc: --3m if mzc itself is running in 3m, --cgc if mzc itself is running in CGC.
5.1 Scheme API for 3m Transformation
| (require compiler/xform) |
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| quiet? : any/c | |||||||||||||||||||||||||||||||||||
| input-file : path-string? | |||||||||||||||||||||||||||||||||||
| output-file : path-string? | |||||||||||||||||||||||||||||||||||
| include-dirs : (listof path-string?) | |||||||||||||||||||||||||||||||||||
| keep-lines? : boolean? = #f |
Transforms C code that is written without explicit GC-cooperation hooks to cooperate with PLT Scheme’s 3m garbage collector; see Overview in Inside: PLT Scheme C API.
The arguments are as for compile-extension; in addition keep-lines? can be #t to generate GCC-style annotations to connect the generated C code with the original source locations.
The file generated by xform can be compiled via compile-extension.