On Wednesday, 21 March 2018 at 16:22:45 UTC, Martin Tschierschke
wrote:
Is there an step by step introduction how to convert a C header
of an external lib into the right extern(C){} block?
A blog post or tutorial, or chapter in a D book? (I have those
from Packt Publishing)
(Especially I am trying to get this used with D:
Montetdb C-API
https://www.monetdb.org/Documentation/Manuals/SQLreference/Programming/MAPI
With:
https://github.com/snaga/monetdb/blob/master/clients/mapilib/mapi.h)
The page: https://dlang.org/spec/interfaceToC.html is known,
but not detailed enough for me.
The easiest thing to do is to write a wrapper in C. The wrapper
will include all necessary headers and provide some easy to use
functions that you can call from D. Of course, you'll need to use
a C compiler to compile it.
Anyway, this header looks very straightforwar, no particular
tricks with the preprocessor. It should be something like this
(untested, obviously):
import core.stdc.stdio : FILE;
enum
{
MAPI_AUTO = 0, /* automatic type detection */
MAPI_TINY = 1,
MAPI_UTINY = 2,
MAPI_SHORT = 3,
MAPI_USHORT = 4,
MAPI_INT = 5,
MAPI_UINT = 6,
MAPI_LONG = 7,
MAPI_ULONG = 8,
MAPI_LONGLONG = 9,
MAPI_ULONGLONG = 10,
MAPI_CHAR = 11,
MAPI_VARCHAR = 12,
MAPI_FLOAT = 13,
MAPI_DOUBLE = 14,
MAPI_DATE = 15,
MAPI_TIME = 16,
MAPI_DATETIME = 17,
MAPI_NUMERIC = 18,
}
enum int PLACEHOLDER = '?';
enum
{
MAPI_SEEK_SET = 0,
MAPI_SEEK_CUR = 1,
MAPI_SEEK_END = 2,
}
enum
{
MAPI_TRACE = 1,
MAPI_TRACE_LANG = 2,
}
alias MapiMsg = int;
enum
{
MOK = 0,
MERROR = -1,
MTIMEOUT = -2,
MMORE = -3,
MSERVER = -4,
}
enum
{
LANG_MAL = 0,
LANG_SQL = 2,
LANG_JAQL = 3,
}
/* prompts for MAPI protocol */
enum int PROMPTBEG = '\001'; /* start prompt bracket */
/* prompt: ready for new query */
const(char)* PROMPT1 = "\001\001\n".ptr;
/* prompt: more data needed */
const(char)* PROMTP2 = "\001\002\n".ptr;
/*
* The table field information is extracted from the table headers
* obtained from the server. This list may be extended in the
future.
* The type of both the 'param' and 'binding'
* variables refer to their underlying C-type. They are used for
* automatic type coercion between back-end and application.
*/
struct MapiStruct;
alias Mapi = MapiStruct*;
/* this definition is a straight copy from
sql/include/sql_query.h */
enum
{
Q_PARSE = 0,
Q_TABLE = 1,
Q_UPDATE = 2,
Q_SCHEMA = 3,
Q_TRANS = 4,
Q_PREPARE = 5,
Q_BLOCK = 6,
}
struct MapiStatement;
alias MapiHdl = MapiStatement*;
alias mapi_uint64 = ulong;
alias mapi_int64 = long;
/* three structures used for communicating date/time information
*/
/* these structs are deliberately compatible with the ODBC
versions
SQL_DATE_STRUCT, SQL_TIME_STRUCT, and SQL_TIMESTAMP_STRUCT */
/* used by MAPI_DATE */
struct MapiDate
{
short year;
ushort month;
ushort day;
}
/* used by MAPI_TIME */
struct MapiTime
{
ushort hour;
ushort minute;
ushort second;
}
/* used by MAPI_DATETIME */
struct MapiDateTime
{
short year;
ushort month;
ushort day;
ushort hour;
ushort minute;
ushort second;
uint fraction; /* in 1000 millionths of a second (10e-9) */
}
/* connection-oriented functions */
extern (C)
{
Mapi mapi_mapi(const char *host,
int port,
const char *username,
const char *password,
const char *lang,
const char *dbname);
// and so on...
}
