Use of library functions of C

[GRANDI GIOVANNI]

Hello,

Having the need to convert some code from QuickBasic 4.5
MicroSoft to PowerBasic 3.5 as this offers more performance,
I have the following problem: to re-use lots of code C 5.10
MicroSoft used as a support to QB where it was not particularly
efficient.

Hoping that I will not have to write the whole code C again,
I would like to ask you if (and how) it is possible to use the
library functions of this language contained in the LLIBCE.LIB.

Thank you, Giovanni Grandi



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[Tom Hanlin]

This is not possible. You can't include the C runtime library in
code that is to be linked with PB/DOS.

You could replace the C runtime routines that you need with your
own code, of course. Also, you can probably find source code for
standard C runtime library routines on the Internet.

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Tom Hanlin
PowerBASIC Staff

[Gerry Dunne]

You would surely have had the same problem linking C code
to QuickBasic? Maybe you haven't used anything from the
runtime library, or you've already figured out how to get
the required routines out of the C runtime library.

I think Tom is perhaps not entirely correct. It is possible
to extract routines from both Microsoft and Borland libraries
and save as object files. These can then be linked to your Basic
program.

You need to use the correct library for the PowerBasic memory
model. Also, if the extracted routine references another
routine in the library, you need to extract that as well, and
link it in too. Where you might run into trouble is with
routines that reference external variables.

I got quite far along with this at one stage. I did successfully
link some code out of the Microsoft C standard libraries. You
might like to give it a go if you're interested in solving
such puzzles. Otherwise Tom's suggestion of downloading
the required code should work.

But I ran into an entirely different problem, that caused me
to abandon the project, or at least postpone it for a while.

I was unable to link any C code I had which included global
pointers. Declaring a global pointer was ok, but any attempt to
do anything with it would cause the link to fail (Error 514:
Invalid fixup).

Since I had a lot of C code I wanted to use, I decided
to do the project in C instead. I haven't got so far with
it that I can't change my mind though, if anyone is able to
assist with the use of C pointers declared globally.

The other area which is difficult when working with C obj
files is getting the segments sorted out correctly. The faq
with PBDOS 3.5 didn't help at all using MS C 5 / Quick C /
Borland C/C++ 4.5. I managed with the latter by fiddling
around with the settings using the IDE and inspecting the
obj files to see what segment names it used.

I hope you do manage to make use of your C code.

Good luck!




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