MAN page from RedHat EL 8 fpc-3.2.0-1.el8.x86_64.rpm
h2pas
Section: Free Pascal C header conversion utility (1)
Updated: 12 Dec 1999
Index NAME
h2pas - The C header to pascal unit conversion program.
SYNOPSIS
h2pas[options] filename
DESCRIPTION
h2pasattempts 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 CONSTRUCTSsection for a full description of what the translator can handle.
USAGE
H2pas is a command-line tool that translates a C header file to a spascalunit. It reads the C header file and translates the C declarations toequivalent 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 asthe 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 bymeans of many options.
OPTIONS
The output of h2pascan be controlled with the following options:
- -d
- use external;for all procedure and function declarations.
- -D
- use externallibname name'func_name'for function and procedure declarations.
- -e
- Emit a series of constants instead of an enumeration type for the C enumconstruct.
- -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 Pin front of pointer type parameters instead of "^".
- -s
- Strip comments from the input file. By default comments are convertedto comments, but they may be displaced, since a comment is handled by thescanner.
- -t
- prepend typedef type names with the letterT(used to follow Borland's convention that all types should be defined withT).
- -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.
CONSTRUCTS
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 argumentsare 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 IFstatement (this is buggy, however).
- preprocessor statements
- the conditional preprocessing commands are recognized and translated intoequivalent pascal compiler directives. The special #ifdef __cplusplusis also recognized and removed.
- typedef
- A typedef statement is changed into a pascal type statement. The followingbasic 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 functionor procedure. - functions and procedures
- functions and procedures are translated as well; pointer types may bechanged to call by reference arguments (using the varargument) by using the -pcommand line argument. functions that have a variable number of argumentsare changed to a function with an array of constargument.
- specifiers
- the externspecifier is recognized; however it is ignored. thepackedspecifier is also recognised and changed with thePACKRECORDSdirective. The constspecifier 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, WINGDIAPIas defined in the win32 headers.If additionally the-xoption is specified then the SYS_TRAPspecifier is also recognized.
- enums
- enum constructs are changed into enumeration types; bear in mind that in Cenumeration types can have values assigned to them; Free Pascal also allowsthis to a certain degree. If you know that values are assigned to enums, itis best to use the -eoption to change the enus to a series of integer constants.
- unions
- unions are changed to variant records.
- structs
- are changed to pascal records, with Cpacking.
SEE ALSO
- ppc386(1)ppumove(1)
Index
- NAME
- SYNOPSIS
- DESCRIPTION
- USAGE
- OPTIONS
- CONSTRUCTS
- SEE ALSO
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