More C to PB Declarations Conversion...

[Scott Wolfington]

struct  GMWnv;
typedef GMWnv *HGMNV;


// GM5S32.DLL business logic functions
long _stdcall GMW_Execute( const char *szFunc, HGMNV hgmnv );


// create, release & copy name value containers
HGMNV __stdcall GMW_NV_Create();

I'm not sure if there is enough information here, but it's all I have. I'm converting a C declaration header file to be used with PB and I came across the code above. What is the struct GMWnv? I know a struct is usually a TYPE in PB, but this struct doesn't have any variables declared within it. I'm not sure how the typedef is being used either. The other thing that's weird (I think) is that the GMWnv struct/typedef isn't being used anywhere in the header file. HGMNV is being used, but that doesn't seem to be declared anywhere.

I'm sure the problem is my ignorance of C, so if anyone can help then I'm all ears.

Thanks a lot,
Scott

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Scott Wolfington
http://www.boogietools.com




[This message has been edited by Scott Wolfington (edited March 05, 2003).]

[JOSE ROCA]

hgmnv is a pointer. Try:

DECLARE FUNCTION GMW_NV_Create LIB "GM5S32.dll" ALIAS "GMW_NV_Create" () AS DWORD
DECLARE FUNCTION GMW_Execute LIB "GM5S32.dll" ALIAS "GMW_Execute" (szFunc AS ASCIIZ, BYVAL hgmnv AS DWORD) AS LONG

GMW_Execute uses the pointer returned by GMW_NV_Create.




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[Scott Wolfington]

Doh! Right, of course. Thanks Jose. What is GMWnv used for?

Also, one more question...

LONG _STDCALL GMW_DS_Query( char *szSQL, char *szFilter ="", char *szFDlm ="\r", char *szRDlm ="\n" );

It looks like szFDlm has a default value of a \r. Is that what that means? Is this possible in PB?

Scott


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Scott Wolfington
http://www.boogietools.com




[This message has been edited by Scott Wolfington (edited March 05, 2003).]

[JOSE ROCA]

It looks like they are optional parameters with default values, but you can't do the same in PB (yet?), you have to pass the values.

Why they use an empty structure to declare a pointer? No idea. C is Chinese to me.




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[Scott Wolfington]

Again, thanks Jose. I appreciate it. Ok, my last question wasn't my last. Here's another:

Should an INT in C be a LONG in PB when converting these declares?

also

Should a LONG in C be a DWORD in PB when converting?

or, do they come over as they are?

Thanks,
Scott


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Scott Wolfington
http://www.boogietools.com




[This message has been edited by Scott Wolfington (edited March 05, 2003).]

[JOSE ROCA]

A C INT is a LONG in 32-bit Windows and an INTEGER in 16-bit Windows. A LONG is a LONG. An UINT (U stands for unsigned) is a DWORD in 32-bit Windows and a WORD in 16-bit Windows. An ULONG is a DWORD.


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[Scott Wolfington]

again, thanks jose. i've been using some tips that lance offered in the below forum link, but this fills in some missing pieces for me.
http://www.powerbasic.com/support/pb...ead.php?t=2696

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scott wolfington
http://www.boogietools.com


[this message has been edited by scott wolfington (edited march 05, 2003).]

[JOSE ROCA]

In the help file there is a section called "Comparative Data Types" that contains a useful table.


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[Scott Wolfington]

Great. Thanks. I was looking for that in the Appendix but couldn't find it. Now I know.

Scott

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Scott Wolfington
http://www.boogietools.com


[This message has been edited by Scott Wolfington (edited March 05, 2003).]

[Scott Wolfington]

Ok, last question, really (for the night anyway).

I've seen some declarations where the pointer asterisk is in different places. For example and using the same function name just as a sample:

LONG _STDCALL GMW_DB_Open( char *szTableName );
LONG _STDCALL GMW_DB_Open( char* szTableName );

Notice the * placement. What's the difference between these?

Scott


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Scott Wolfington
http://www.boogietools.com


[This message has been edited by Scott Wolfington (edited March 05, 2003).]

[JOSE ROCA]

Nothing, as far as I know. It is a pointer to an as ASCIIZ string, so you can translate it to PB as szTableName AS ASCIIZ.


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[Cecil L. Williams]

Scott,

Jose is right. The * either place is fine. Just a matter
of coding style. I like the second one best where the pointer
designation is just after the type specifier.

Cheers,
Cecil

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[This message has been edited by Cecil L. Williams (edited February 27, 2003).]

[Lance Edmonds]

The "Comparative Data Types" topic in the PB/Win 6.1x and PB/Win 7.0 help files is highly recommended reading, and can answer a lot of those "what's this translate to in PowerBASIC" questions...


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Scott Wolfington]

Thanks Jose, Cecil, and Lance.

Lance, you're a little late to the party. Jose mentioned that same help file topic above.

Again, thanks guys.

Cheers,
Scott


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Scott Wolfington
http://www.boogietools.com


[This message has been edited by Scott Wolfington (edited March 05, 2003).]