C2L(10.1)                                               C2L(10.1)

     NAME
          c2l - C to Limbo translator

     SYNOPSIS
          c2l [ option ... ] file

     DESCRIPTION
          C2l translates the named C file into Limbo. The translated
          code should be almost always syntactically correct but will
          certainly never be semantically correct as certain con-
          structs in C (strings for example) are almost impossible to
          convert automatically into Limbo.  Otherwise it tries to do
          a good job of translating the C constructs that have some
          sort of equivalence in Limbo. The C ternary ?: operator is
          replaced where possible.  C library calls are mapped to
          calls to the Limbo system module, maths module or the pro-
          vided Limbo libc modules. Some library calls, such as mal-
          loc, are instead mapped directly into Limbo wherever possi-
          ble.

          Once a translation has been made, running the limbo(1) com-
          piler on the resulting output should pick out the areas
          where hand editing is required.

          C2l normally puts all mapped C code (plus that from included
          files) into a single .b file.

          The options to c2l are:

          -p   Use an ANSI preprocessor in place of the internal one.

          -Dname=def
          -Dname
               Define the name to the preprocessor, as if by
               `#define'.  If no definition is given, the name is
               defined as `1'.

          -Idir
               An `#include' file whose name does not begin with slash
               or is enclosed in double quotes is always sought first
               in the directory of the file argument.  If this fails,
               or the name is enclosed in <>, it is then sought in
               directories named in -I options, then in /sys/include,
               and finally in /$objtype/include.

          -m   Put the mapped code of any included .h files into its
               corresponding .m file instead of the .b file.

          -i   Send the mapped code of any included .h files to
               /dev/null.

     C2L(10.1)                                               C2L(10.1)

          -l   Send the mapped code of any non-local included .h files
               to /dev/null.

          -c   Just generate code corresponding to the C code ie don't
               include any prologue or epilogue code such as an imple-
               ment header, include declarations, module declarations
               or an init function.

          -v   Outputs any warnings to standard error as well as put-
               ting them in the output source.

          -s   Map C strings to NUL-terminated arrays of bytes in
               Limbo. This just about preserves the semantics of
               strings and makes the process of hand editing much eas-
               ier. It is useful as a first attempt at translation. In
               this case the module /module/libc0.m is used in place
               of the standard one /module/libc.m.

          -S   Map char* in C to string in Limbo. Incompatible with
               the -s option.

          -M   Indicates this file is the one containing the C main
               program. Used with the -q option below when c2l does
               not always know this until it's too late.

          -q   This reduces the number of passes that c2l makes over
               the C code. It makes it faster but more liable to miss
               some transformations. Cyclic data structures might not
               be detected.

          -a   For functions which are passed the address of a scalar
               typed (ie not a structure or union) expression as a
               parameter, pass the expression itself and rewrite the
               function and all calls of it to return the expression.
               For example :-

                    int
                    f(int x, int *y)
                    {
                         *y = x*x*x;
                         return x*(*y);
                    }

                    void
                    g()
                    {
                         int p3, p4;

                         p4 = f(1729, &p3);
                    }

                    becomes

     C2L(10.1)                                               C2L(10.1)

                    f(x: int, y: int): (int, int)
                    {
                         y = x*x*x;
                         return (x*y, y);
                    }

                    g()
                    {
                         p3, p4: int;

                         (p4, p3) = f(1729, p3);
                    }

          C2l runs the preprocessor on the C code before starting
          translation. As a special case it will convert definitions
          of constants into Limbo constant declarations.  It makes no
          attempt to convert any definitions into function declara-
          tions.

          Identifier names that clash with Limbo keywords have letter
          x appended so, for example, a structure member called type
          would become typex.

          Warning messages preceded by the acronym TBA (to be
          addressed) are issued for NUL bytes in strings, ... as an
          argument, array indices in declarations, use of void type,
          use of unions, bit fields, use of address operator, negative
          array indices, element specifiers, initial values in Limbo
          modules, labels, gotos and case statement fall through.

          The C types char and unsigned char are mapped to the Limbo
          byte type.  The C types short, unsigned short, int, unsigned
          int, long and unsigned long are mapped to the Limbo int
          type. The C types long long and unsigned long long are
          mapped to the Limbo big type. Finally the C types float and
          double are mapped to the Limbo real type.

          Anonymous C structures and unions map to a name of the form
          <module>_adt_<num> where module is the name of the module
          which is, in turn, derived from the file name. Anonymous
          member names in strucures and unions have a name of the form
          anon_<num>. Finally,temporary variables generated by c2l
          have a name of the form tmp_<num>. In all cases <num> is a
          unique identifier.

     SOURCE
          /module/libc.m
          /module/libc0.m
          /appl/lib/libc.b
          /appl/lib/libc0.b