| Forum List • Thread List • Refresh • New Topic • Search • Previous • Next  1  |  1. DLL return value compatibility#5704 Posted by: 2005-01-13 00:21:11 | I am trying to map the SQLITE3.DLL. But I am not sure how to map functions that use double, int64 or utf16 string encoding.
Is the C double type, the same as Rapid-Q's DOUBLE?
Does Rapid-Q have a 64-bit integer type? It appears LONG is only 32 bits, and that is the longest integer I saw. The C API declares it as "long long int". Any ideas how I can use this return value? (sqlite3_last_insert_rowid returns this 8 byte monster, and as that can be a very important function, I want to try to be able to use it.)
Can Rapid-Q handle utf16 text? I don't recall ever seeing that it does, but if someone can tell me otherwise, and point me to details on it, I will try to map those functions as well.
Thanks,
David | 2. Re: DLL return value compatibility #5705 Posted by: JohnK 2005-01-13 05:05:01 | You are entering a grey zone with rapidQ here. HotBasic is your better option here. But if that is not possible and you need RQ, then you can "handle" these numbers by only if variables are passed from the DLL by reference (i.e., BYREF MyNum AS LONG). Get the pointer then use CPYMEM to move the bits over to a string pointer *yes string* of correct dimensions. Then you have to always be doing the math yourself! (Offset+base)
In windows a long_Long_int is a structure--in RQ it is something like this
TYPE LONG_LONG_INTEGER
lowword AS DWORD
highword AS DWORD
END TYPE
>
C double type, the same as Rapid-Q's DOUBLE?
probably, find out the #bytes used by C DOUBLE, I am pretty sure a float is the same as SINGLE
>
Does Rapid-Q have a 64-bit integer type?
No, you would have to put together your own math calculations with Doubles and work with the rounding errors.
This isn't fun stuff, but is probably possible with work.
I'm basic too | 3. Re: DLL return value compatibility #5706 Posted by: 2005-01-13 07:05:15 | Looks like the C double and the RQ double are the same number of bytes (8 each), so hopefully I can just transfer them.
the functions are returning the 64bit integers by value.
I am thinking a workaround is to declare the function as double (since that is 8 bytes), then memcopy the 8 bytes into the low four bytes into a 4 byte integer. (And if someone is trying to create a 200 billion plus record database, they ain't gonna be coding it in rapid-q. so I think it is safe to dump the high bytes.
DECLARE FUNCTION DLL_function .... AS DOUBLE
FUNCTION my_function .... AS LONG
DIM d AS DOUBLE
DIM l AS LONG
d = DLL_function()
memcpy VARPTR(l),VARPTR(d),4
result = l
END FUNCTION
Do you think this will work?
David | 4. Re: DLL return value compatibility #5708 Posted by: OvalX 2005-01-13 23:06:39 | | I'd like to work with SQLite3.dll too, but I don't know how to use declarations of commands like sqlite3_open and sqlite3_exec (or other basic database commands). I welcome simply code example... Thanx. Slavo | 5. Re: DLL return value compatibility #5710 Posted by: 2005-01-13 23:24:54 | OvalX,
I'm still working on it, but for open, this should work:
CONST SQLITE_OK = 0
declare function sqlite3_open LIB "SQLITE3.DLL" ALIAS "sqlite3_open" (byref filename as string, byref db as long) as long
declare function sqlite3_close LIB "SQLITE3.DLL" ALIAS "sqlite3_close" (db as long) as long
dim db as long
if sqlite3_open("test.db",db)=SQLITE_OK then
' database opened successfully.
sqlite3_close(db)
end if
For the exec, I only use it to do action queries, and as such has not played with using the callback.
declare sqlite3_exec LIB "SQLITE3.DLL" ALIAS "sqlite3_exec" (db as long, byref sql as string, pCallback as long, pUserData as long, byref pErrMsg as long) as long
'run a query
if sqlite3_exec(db,"DELETE * FROM T1;", 0,0,0)=SQLITE_OK then
'query ran okay
end if
By the end of this week, I hope to have tested how to use the pCallback, pUserData and pErrMsg arguments. For action queries, they can simply be set to 0.
David | 6. Re: DLL return value compatibility #5711 Posted by: 2005-01-14 02:14:07 | Errors in my last post
For sqlite3_open, you must put the filename in a string variable and pass that to the function
dim filename as string
filename = "test.db"
sqlite3_open(filename, db)
With sqlite3_exec, the declaration should be:
declare function sqlite3_exec LIB "SQLITE3.DLL" ALIAS "sqlite3_exec" (db as long, byref sql as string, pCallback as long, pUserData as long, ppErrMsg as long) as long
for the ppErrMsg, use must specify either
dim pErrmsg as long
dim sql as string
sql = "Delete * from T1;"
sqlite3_exec(db, sql, 0, 0, varptr(pErrMsg) )
then if it returns an error you must declare and call
sqlite3_free(pErrMsg)
or
sqlite3_exec(db, sql, 0, 0, 0 )
then if there is an error, get the error message from sqlite3_errmsg(db)
David | 7. Re: DLL return value compatibility #5885 Posted by: OvalX 2005-02-22 15:07:22 | 2005-Feb-19 - SQLite version 3.1.3 Released!!!
Version 3.1.3 cleans up some minor issues discovered in version 3.1.2.
Thanx for hint, David! Slavo
This example code works for me:
$TYPECHECK ON
CONST sqlite3_ok = 0
DECLARE FUNCTION sqlite3_open LIB "SQLITE3.DLL" ALIAS "sqlite3_open" (byref filename AS STRING, byref db AS LONG) AS LONG
DECLARE FUNCTION sqlite3_close LIB "SQLITE3.DLL" ALIAS "sqlite3_close" (db AS LONG) AS LONG
DECLARE FUNCTION sqlite3_exec LIB "SQLITE3.DLL" ALIAS "sqlite3_exec" (db AS LONG, byref sql AS STRING, pCallback AS LONG, pUserData AS LONG, ppErrMsg AS LONG) AS LONG
DECLARE FUNCTION sqlite3_get_table LIB "SQLITE3.DLL" ALIAS "sqlite3_get_table" (db AS LONG, sql AS STRING, lpTable AS LONG, nRow AS LONG, nColumn AS LONG, lpErrMsg AS LONG) AS LONG
DECLARE FUNCTION sqlite_free_table LIB "SQLITE3.DLL" ALIAS "sqlite3_free_table" (lpTable AS LONG) AS LONG
DIM db AS LONG
DIM filename AS STRING
filename = "data.db"
IF FILEEXISTS(CURDIR$ + "\" + filename) THEN KILL CURDIR$ + "\" + filename
IF sqlite3_open (filename, db) = sqlite3_ok THEN
PRINT "database opened successfully on " + TIME$
PRINT
DIM sql AS STRING
DIM nrows AS LONG
DIM ncolumns AS LONG
DIM perrmsg AS LONG
DIM lptable AS LONG
DIM result AS LONG
DIM lerrmsg AS LONG
DIM ipos AS INTEGER
DIM bcar AS BYTE
DIM litems AS LONG
DIM prow AS LONG
DIM pcol AS LONG
DIM sversion AS STRING
DIM icounter AS LONG
DIM nfila AS LONG
DIM i AS BYTE
sql = "create table table1(" + _
"strings varchar(10)," + _
"numbers int" + _
");"
sqlite3_exec (db, sql, 0, 0, 0)
sql = "begin;"
sqlite3_exec (db, sql, 0, 0, 0)
FOR i = 1 TO 20
sql = "insert into table1 values('text" + STR$(i) + "', '" + STR$(21 - i) + "');"
sqlite3_exec (db, sql, 0, 0, 0)
NEXT i
sql = "commit;"
sqlite3_exec (db, sql, 0, 0, 0)
sql = "select * from table1"
result = sqlite3_get_table (db, sql, VARPTR(lptable), VARPTR(nrows), VARPTR(ncolumns), VARPTR(perrmsg))
IF result = sqlite3_ok THEN
nfila = -1
PRINT "--- dump database ---"
FOR litems = 0 TO (nrows * ncolumns) + 1
pcol = (litems MOD ncolumns)
IF pcol = 0 THEN
nfila = nfila + 1
sversion = STR$(nfila) + CHR$(9)
END IF
memcpy VARPTR(prow), lptable + (4 * litems), 4
icounter = 0
DO
memcpy VARPTR(bcar), prow + icounter, 1
IF (bcar = 0) THEN EXIT DO
sversion = sversion + CHR$(bcar)
icounter++
LOOP
IF pcol = 0 THEN
sversion = sversion + CHR$(9)
ELSE: PRINT sversion
END IF
NEXT
sqlite_free_table VARPTR(lptable)
PRINT "------ end dump -----"
ELSE
PRINT "error in sqlite_get_table: ", lerrmsg
END IF
sqlite3_close(db)
PRINT
PRINT "database closed on " + TIME$
SHOWMESSAGE "number of rows: " + STR$(nrows) + CHR$(13) + _
"number of columns: " + STR$(ncolumns) + CHR$(13)
END IF
| | Forum List • Thread List • Refresh • New Topic • Search • Previous • Next 1 |
|
|
搜索
论坛
Home
回顶部
g.yi.org Hits:0
