API function won't compile using CYGWIN g++; Interpreting error message

On 31 Jan 2004 13:01:03 -0800, Join Bytes! (Roger Sherman) wrote:
[color=blue]
>I'm using CYGWIN g++. I'm having trouble making an API call the
>WindowFromPoint function.
>Here is my code.
>
>
>FILE: t.cc
>#include <windows.h>
>int main () {
>
>POINT p;
>p.x=200;
>p.y=200;
>
>HWND window_handle;
>
>window_handle = WindowFromPoint(p);
>
>return 0;
>}
>
>
>Here is the error message I'm getting:
>
>C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0x 22):t.cc: undefined
>reference to 'WindowFromPoint@8'
>
>Could someone please tell me
>1)What this error means, specifically, and;
>
>2)What I need to do to fix it
>
>Thank you
>Jeff[/color]
See the answers you get to the same question in
alt.comp.lang.learn.c-c++. If you must post to multiple groups, do it
with a single message, not an individual one to each group.


<<Remove the del for email>>

Hello,

"Roger Sherman" <halusa@erols.com> a écrit dans le message de news:
Join Bytes!...[color=blue]
> I'm using CYGWIN g++. I'm having trouble making an API call the
> WindowFromPoint function.
> Here is my code.
>
>
> FILE: t.cc
> #include <windows.h>
> int main () {
>
> POINT p;
> p.x=200;
> p.y=200;
>
> HWND window_handle;
>
> window_handle = WindowFromPoint(p);
>
> return 0;
> }
>
>
> Here is the error message I'm getting:
>
> C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0x 22):t.cc: undefined
> reference to 'WindowFromPoint@8'
>
> Could someone please tell me
> 1)What this error means, specifically, and;[/color]

Although it's not a C problem as it's commonly discussed here, I *can* think
it's a linkage problem.
The linker can't resolve this name (WindowFromPoint) because you didn't
specify to your linker the library in which this function is stored.
[color=blue]
> 2)What I need to do to fix it[/color]

You need to link your program with user32.lib

best regards, regis

Roger Sherman wrote:[color=blue]
>
> I'm using CYGWIN g++. I'm having trouble making an API call the
> WindowFromPoint function.
> Here is my code.
>
> FILE: t.cc[/color]

sounds like a C++, not C program.
[color=blue]
> #include <windows.h>[/color]

definitely non-standard header.
[color=blue]
> int main () {
>
> POINT p;[/color]

undefined type POINT
[color=blue]
> p.x=200;
> p.y=200;
>
> HWND window_handle;[/color]

Undefined type HWND. declaring variable after executable code.
[color=blue]
>
> window_handle = WindowFromPoint(p);[/color]

Undeclared function.
[color=blue]
>
> return 0;
> }
>
>
> Here is the error message I'm getting:
>
> C:\DOCUME~1\jeff\LOCALS~1\Temp\ccIIB5F0.o(.text+0x 22):t.cc: undefined
> reference to 'WindowFromPoint@8'[/color]

Now we know you are using a C++ compiler. Off topic on c.l.c
[color=blue]
>
> Could someone please tell me
> 1)What this error means, specifically, and;
>
> 2)What I need to do to fix it[/color]

Get thee to a newsgroup where this is topical. The windows
contamination means c.l.c++ is not it. That, and the c++ code,
means c.l.c is not it. Maybe you should look for a group with the
word 'windows' in it.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!