s2cc(1) Scheme to C compiler


s2cc [ option ] ... file ...


The s2cc command (previously known as scc) invokes a Scheme compiler which accepts the language defined in the essential portions of Revised4 Report on the Algorithmic Language Scheme, with minor constraints and some additions. The compiler produces C source files which are then compiled using the system's C compiler to produce conventional .o and a.out files. The C code produced by this compiler may be intermixed with other C code or code written in other languages.


These options are accepted by s2cc. Other options will be assumed to be options of the system's C compiler and they will be passed to it when it is invoked.
-cc C compiler
Compile the Scheme compiler produced C code with C compiler. If this flag is not supplied, then the C compiler cc will be used.
Compile the Scheme programs found in the files source.sc and leave the resulting code in source.c files. No further operations are performed.
-I directory
Specifies a directory to be searched by include for source files.
-f symbol value
Define the compile-time constant symbol to value. This is equivalent to the construct (define-constant symbol value) appearing in the Scheme source.
Combine the source and object files into a Scheme interpreter. The module name for each Scheme source file is automatically determined. Module names for previously compiled modules must be specified using the -m option.
-m module-name
Specifies the name of a previously compiled module. Note that the Scheme compiler will downshift the alphabetic characters in the module-name. Modules are initialized in the order that the -m flags appear.
Optimize code by omitting bounds checks on vectors and strings.
Optimize code by omitting stack trace-back code.
Optimize code by assuming that all numbers are fixed point.
Optimize code by omitting type error checks.
Produce profiled code for run-time measurement using gprof(1). The profiled library is used in lieu of the standard Scheme library.
-scgc statflag
Enables garbage collection statistics. If set to 1, then garbage collection statistics will be printed. The default is 0, that will result in no statistics.
-sch heap
Specifies the compiler's initial heap size in megabytes. The default is system dependent.
-scl percent
Specifies the percent of the heap allocated after a generational garbage collection that will force a full collection. The default is 40.
-scmh heap
Specifies the compiler's maximum heap size in megabytes. The default is five times the initial size of the heap.
-LIBDIR directory
Specifies a directory containing the files: predef.sc, objects.h, libs2c.a, and optionally libs2c_p.a.
Logs information internal to the compiler to the C source file produced by the compiler. Each type of information is controlled by a flag: -source, -macro, -expand, -closed, -transform, -lambda, -tree, -lap, -peep. The flag -log is equivalent to specifying the flags: -source, -macro, -expand, -closed, -transform, -lambda, -tree.


The items controlled by -sc.. flags can also be controlled by environment variables. If both the flag and the environment variable are provided, then the flag's value will be used.
Controls the reporting of garbage collection statistics to the standard error file. If set to 1, then garbage collection statistics will be printed. The default setting is 0 that will not print the statistics.
Specifies the initial size of the heap in megabytes. The default heap size is system dependent.
Specifies the percent of the heap allocated after a generational garbage collection that will force a full collection. The default is 40.
Specifies the maximum size of the heap in megabytes.


Following the command options come one or more file names.
Scheme source. Scheme source files will be compiled into C files with the name name.c.
C source.
Assembly language source.
Object file which may have been generated by any compiler.
Object file archive which may have been generated by any compiler.


The disgnostic messages produced by the compiler are printed on the standard error file.


/.../schemetoc/...  source and documentation

/.../libs2c.a      library

/.../libs2c_p.a    profiled library (optional)

/.../s2cc          shell script

/.../s2ccomp       compiler

/.../predef.sc     predefined functions

/.../objects.h     definitions "#include'd" in the C code

SC-TO-C.c          temporary C source file

source.S2C         temporary C source file

SC-TO-C.o          temporary object file


When the compiler is able to identify every call to a procedure, it is able to generate it "in-line", and perform tail calls by using "goto". This analysis covers most loops, conditional expressions, and finite state machines. For non-tail recursive calls, the code generated by the compiler uses the standard C mechanisms for procedure call and return. This therefore requires that each top-level Scheme procedure, and any Scheme procedure which has more than one call which is not tail-recursive be compiled into its own C procedure. Calls to such procedures will be tail-recursive if and only if the host C compiler optimizes tail-recursion.