h2pas - The C header to pascal unit conversion program.
h2pas attempts to convert a C header file to a pascal unit.
it can handle most C constructs that one finds in a C header file, and
attempts to translate them to their pascal counterparts. see the
CONSTRUCTS section for a full description of what the translator can
handle.
H2pas is a command-line tool that translates a C header file to a
spascal unit. It reads the C header file and translates the C declarations
to equivalent pascal declarations that can be used to access code written in
C.
The output of the h2pas program is written to a file with the same
name as the C header file that was used as input, but with the extension
.pp. The output file that h2pas creates can be customized in a number
of ways by means of many options.
The output of h2pas can be controlled with the following
options:
- -d
- use external; for all procedure and function declarations.
- -D
- use external libname name 'func_name' for
function and procedure declarations.
- -e
- Emit a series of constants instead of an enumeration type for the C
enum construct.
- -i
- create an include file instead of a unit (omits the unit header).
- -l libname
- specify the library name for external function declarations.
- -o outfile
- Specify the output file name. Default is the input file name with the
extension replaced by .pp "."
- -p
- use the letter P in front of pointer type parameters instead of
"^".
- -s
- Strip comments from the input file. By default comments are converted to
comments, but they may be displaced, since a comment is handled by the
scanner.
- -t
- prepend typedef type names with the letter T (used to follow
Borland's convention that all types should be defined with T).
- -v
- replace pointer parameters by call by reference parameters. Use with care
because some calls can expect a NIL pointer.
- -w
- Header file is a win32 header file (adds support for some special
macros).
- -x
- handle SYS_TRAP of the PalmOS header files.
The following C declarations and statements are recognized:
- defines
- defines are changed into pascal constants if they are simple defines.
macros are changed - wherever possible to functions; however the arguments
are all integers, so these must be changed manually. Simple expressions in
define staments are recognized, as are most arithmetic operators:
addition, subtraction, multiplication, division, logical operators,
comparison operators, shift operators. The C construct ( A ? B : C) is
also recognized and translated to a pascal construct with an IF statement
(this is buggy, however).
- preprocessor
statements
- the conditional preprocessing commands are recognized and translated into
equivalent pascal compiler directives. The special #ifdef
__cplusplus is also recognized and removed.
- typedef
- A typedef statement is changed into a pascal type statement. The following
basic types are recognized:
- char
- changed to char.
- float
- changed to real (=double in free pascal).
- int
- changed to longint.
- long
- changed to longint.
- long int
- changed to longint.
- short
- changed to integer.
- unsigned
- changed to cardinal.
- unsigned char
- changed to byte.
- unsigned int
- changed to cardinal.
- unsigned long int
- changed to cardinal.
- unsigned short
- changed to word.
- void
- ignored.
These types are also changed if they appear in the arguments of a function or
procedure.
- functions and
procedures
- functions and procedures are translated as well; pointer types may be
changed to call by reference arguments (using the var argument) by
using the -p command line argument. functions that have a variable
number of arguments are changed to a function with an array of
const argument.
- specifiers
- the extern specifier is recognized; however it is ignored. the
packed specifier is also recognised and changed with the
PACKRECORDS directive. The const specifier is also
recognized, but is ignored.
- modifiers
- If the -w option is specified, then the following modifiers are
recognized: STDCALL , CDECL , CALLBACK ,
PASCAL , WINAPI , APIENTRY , WINGDIAPI as
defined in the win32 headers. If additionally the -x option is
specified then the SYS_TRAP specifier is also recognized.
- enums
- enum constructs are changed into enumeration types; bear in mind that in C
enumeration types can have values assigned to them; Free Pascal also
allows this to a certain degree. If you know that values are assigned to
enums, it is best to use the -e option to change the enus to a
series of integer constants.
- unions
- unions are changed to variant records.
- structs
- are changed to pascal records, with C packing.
-