BLOB and Automation - C / C++ / MFC Discussion Boards

FILE in memory

Davide Pizzolato3-Sep-01 5:59

Davide Pizzolato

3-Sep-01 5:59

Is it possible to create, open, use, close and delete a FILE in memory, without flushing to disk?

Re: FILE in memory

C^hris L^osinger3-Sep-01 6:40

C^hris L^osinger

3-Sep-01 6:40

i don't think so. but if you use Windows HANDLEs (CreateFile and friends) you can use memory or file based I/O transparently.

-c

------------------------------
Smaller Animals Software, Inc.
http://www.smalleranimals.com

Re: FILE in memory

Davide Pizzolato3-Sep-01 10:18

Davide Pizzolato

3-Sep-01 10:18

Maybe the only way is the FILE_ATTRIBUTE_TEMPORARY flag; probably the same than tmpfile().
How long can I keep the file open before the OS flushes?

Read from file

3-Sep-01 4:15

How can I read from a file?

for Example I have a file = test.txt
and than... I have a string

and now I want that the text from my test.txt file be copied in my String;
how can I do this?
is this the right way?

CString str;
CFile file("test.txt", CFile::modeRead);
file.Read( ... and then?

MessageBox(str); // to se what is in the test.txt Confused | :confused:

Re: Read from file

3-Sep-01 4:23

Go and buy a book about the C/C++ programming language.

Re: Read from file

Michael P Butler3-Sep-01 5:45

Michael P Butler

3-Sep-01 5:45

If it's just a text file try using CStdioFile and calling the method ReadString

CString str; 
CStdioFile file("test.txt", CFile::modeRead); 
file.ReadString(str);
MessageBox(str); // to se what is in the test.txt

Michael

Re: Read from file

4-Sep-01 1:52

thank you! Smile | :)

BLOB and Automation

Paul Selormey3-Sep-01 3:22

Paul Selormey

3-Sep-01 3:22

What is the best way to handle BLOB in automation interface? IStream seems to be a good candidate, anything different?

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan, and open for programming contract anywhere!

dbopen() fails

3-Sep-01 0:17

Hello,

I am writing a program that access a MSSQL 2000 3 times, in a windows 2000 evirenoment.

The problem is that the dbopen() function fails randomly in one of the 3 times it tries to open the database the error says:

DB-LIBRARY error:
NULL DBPROCESS pointer encoutred.

it happens that sometimes the program runs without errors.

the same program was running before on a windows NT4 /MSSQL 7 without problems.

Using DLL in Internet Explorer

sanskypotov3-Sep-01 0:13

sanskypotov

3-Sep-01 0:13

Hi ,
I have a dll , which displays a dialog box. and I need to
invoke this dialog through a HTML page. There would be a
string send from the HTML to the dialog , and after processing, from the Dialog back to the HTML page.
Can someone please tell how can I achieve this.
Thanks
Sanksy ;-D

sp
Big Grin | :-D

Re: Using DLL in Internet Explorer

Paul Selormey3-Sep-01 3:25

Paul Selormey

3-Sep-01 3:25

Ordinary DLLs are not normally used, at least not easily in IE. Convert it to a COM server or write a simple COM server to access the DLL.

Best regards,
Paul.

Paul Selormey, Bsc (Elect Eng), MSc (Mobile Communication) is currently Windows open source developer in Japan, and open for programming contract anywhere!

Re: Using DLL in Internet Explorer

Michael P Butler3-Sep-01 3:29

Michael P Butler

3-Sep-01 3:29

I'm assuming the DLL is installed client side and not on the server.

You could create a COM DLL and launch the COM object from the VBScript/JavaScript with CreateObject

or you could possible using an ATL composite control and embed the dialog in the HTML page.

Michael Smile | :)

Re: Using DLL in Internet Explorer

sanskypotov3-Sep-01 3:59

sanskypotov

3-Sep-01 3:59

Thanks for the help.

If the DLL happens to be a Normal DLL, so in such case how
do I handle it?
Thanks -n- Regards,
sanjay Big Grin | :-D

Re: Using DLL in Internet Explorer

Michael P Butler3-Sep-01 22:18

Michael P Butler

3-Sep-01 22:18

You'll need to write a COM wrapper DLL which calls your DLL functions. The ATL wizard will generate a simple com object, add a method called ShowDialog and then put the call to the DLL in the generated function.

It's a bit of a hack but should allow you to call your DLL from a HTML page.

Michael Smile | :)

Re: Check DelayLoadProfile in MSJ

Masaaki Onishi3-Sep-01 5:52

Masaaki Onishi

3-Sep-01 5:52

Hello, the codegurus around the world.;)

I think that we may use DelayLoadProfile approaches.

That is, we can insert this DLL process in IE process,
and hook some function to show HTML page.
(Humm, IE may use COM, so hook socket?) Dead | X|

Good luck.

Have a nice day!

-Masaaki Onishi-

mapping a va_list (...) in another function call

2-Sep-01 22:37

Hi,

i have a function:
void Trace ( const int nTraceLevel, const _TCHAR *pszMessage, ... ) const;

but i want to be able to call this function without specifying the Tracelevel.
so i want to declare another function like this

void Trace ( const _TCHAR *pszMessage, ... ) const;

which then calls the othere trace function with nTraceLevel = 0
But calling it like this fails:
Trace ( 0, pszMessage, ... );

It have me an error when i tried to do that. Is it possible to do that?
If so, how?

Thanks,
Bene

Re: mapping a va_list (...) in another function call

Rashid Thadha2-Sep-01 23:59

Rashid Thadha

2-Sep-01 23:59

e.g.

va_list args;
va_start(args, pszMessage);

Trace(0, pszMessage, args);
va_end(args);

Re: mapping a va_list (...) in another function call

3-Sep-01 22:09

hhmm, i spoke to soon. it at least compiles but when i get the info in my main trace functions, the values it gets from the va list are invalid.
any other suggestions?

Re: mapping a va_list (...) in another function call

The_Server3-Sep-01 13:02

The_Server

3-Sep-01 13:02

I don't realy understand what you want. Confused | :confused:

but I have a define for ya:

#define GetParam(arg,num) (((int *)(&arg))[num])

the GetParam will give you the arguments of the function.

e.g.

func(const char * format, ...)

and call it like this

func("%d %s %c", 123, "123", 's');// the %d%s%c is not importent

than use the get param like this:

int a=(int)GetParam(format,1);  // 123
char * b=(char *)GetParam(format,2); // "123"
char c=(char)GetParam(format,3); // 's'

NOTE: on a 32bit OS you'll have a little problem getting the __int64 value (I'll let u discover yourself how to do that);)

BTW: for some of you that wished for CodeProject irc server
I create a channle on DalNet called "#CodeProject"

Re: mapping a va_list (...) in another function call

Tim Smith3-Sep-01 13:36

Tim Smith

3-Sep-01 13:36

Ack, never write your own argument list picking function. They aren't at all portable. (But of course, if you don't care about portability, more power to you!)

Tim Smith
Descartes Systems Sciences, Inc.

Re: mapping a va_list (...) in another function call

The_Server4-Sep-01 13:13

The_Server

4-Sep-01 13:13

I've been throe HELL, trying to understand the CRT source code, printf for example.

and believe me, it's not much fun. Wink | ;)

(i'm still confused)

Portable ? depends on the operating system.
if it's a 16bit OS, arg picking will be by 16 bits pieces.
if it's a 32bit OS, arg picking will be by 32 bits pieces.
if it's a 64bit OS, arg picking will be by 64 bits pieces.
if it's a 128bit OS, arg picking will be by 128 bits pieces.
if it's a 512bit OS, arg picking will be by 512 bits pieces. Smile | :)

...

that's all.
And in order to make portable I have a #define SYSBITS __int32

BTW: for some of you that wished for CodeProject irc server
I create a channle on DalNet called "#CodeProject"

Re: mapping a va_list (...) in another function call

Tomasz Sowinski3-Sep-01 13:48

Tomasz Sowinski

3-Sep-01 13:48

on a 32bit OS you'll have a little problem getting the __int64 value

Not only that. double numbers will be more serious problem.

Tomasz Sowinski -- http://www.shooltz.com

Re: mapping a va_list (...) in another function call

The_Server4-Sep-01 12:50

The_Server

4-Sep-01 12:50

well to got the 64 bits value (e.g. __int64 or double) we do it like this:
(*** lets say we're working on a 32bit OS ***)
in the .h file:

#define GetParam(arg,num) (((int *)(&arg))[num])
func1(const char *lll, ...);

The arguments come in 32 bits pieces.
There for the 64bits variable will come in 2 pieces (64/32=2). Smile | :)

and we will get the value like this

func1(const char *lll, ...)
{
    __int64 l_nNumber;  // a 64 bits unit to store the data
    int pos=0; // the current position of the args: 0=lll, 1=next val,2= 3rd,...
 
    ((__int32 *)&l_nNumber)[0]= GetParam(lll, ++pos); // copy the 1st 32bits
    ((__int32 *)&l_nNumber)[1]= GetParam(lll, ++pos); // copy the 2st 32bits
 
    //BTW: works same way on double
}

BTW: for some of you that wished for CodeProject irc server
I create a channle on DalNet called "#CodeProject"

Re: mapping a va_list (...) in another function call

Tomasz Sowinski5-Sep-01 1:26

Tomasz Sowinski

5-Sep-01 1:26

1) Do you think it's better than va_xxx?

2) Do you think this solves the original poster's problem?

Tomasz Sowinski -- http://www.shooltz.com

Re: mapping a va_list (...) in another function call

The_Server8-Sep-01 14:07

The_Server

8-Sep-01 14:07

1) what is the "original poster's problem"?
2) I have no problem with it, as a matter of fact it works perfect.

BTW: for some of you that wished for CodeProject irc server
I create a channle on DalNet called "#CodeProject"

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