C / C++ / MFC

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Selecting an area with the mouse Rage4-Mar-02 6:17 Rage 4-Mar-02 6:17  Hi ! I´m currently coding an application that displays graphically mathematical curves (with a CDC). I´d like to implement a zoom on it, that is: the user clicks, and when he moves the mouse while holding the mouse button down, the prg draws a rectangle with dot lines. When the user stops maintaining the mouse button down, it zooms-in. (The whole thing acts like selecting two or more icons on the desktop of windows, for example). Well, i actually want to know an easy way to draw the rectangle with dot lines ... because I suppose it must be another way than saving the background, drawing the rectangle, and - when the user moves - redisplaying the saved background and redrawing the rectangle, must´nt it? RaGe Unfortunately, brute-force solutions tend to be slow even when performed by modern-day microcomputers, which are capable of several MIPS except when I'm late for an appointment and want to finish a compile and run just one more test before I leave, in which case the crystal in my computer is apparently designed to automatically revert to 1 Hz. -- Michael Abrash Re: Selecting an area with the mouse Tomasz Sowinski4-Mar-02 6:15 Tomasz Sowinski 4-Mar-02 6:15  Try DrawFocusRect. It works in XOR mode - drawing it twice removes it from the screen. Tomasz Sowinski -- http://www.shooltz.com Re: Selecting an area with the mouse Joaquín M López Muñoz4-Mar-02 7:04 Joaquín M López Muñoz 4-Mar-02 7:04  An alternative to Tomasz' suggestion is using <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcmfc98/html/_mfc_crecttracker.asp">CRectTracker</a>. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Simple but Painfully Annoying ScottS4-Mar-02 5:34 ScottS 4-Mar-02 5:34  I am very close to losing my sanity trying to build some code with visual c++. I am sure the problem will have a very simple solution but i could do with some help none the less. I have a program with six source code files and six associated header files, they all compile fine but when trying to link i get the following error. test.obj : error LNK2001: unresolved external symbol "void __cdecl mht_associate(struct tracker_struct * *,struct measurements_struct * *,struct parameter_struct *,int,double * * *,int,int,int,int)" (?mht_associate@@YAXPAPAUtracker_struct@@PAPAUmeas urements_struct@@PAUparameter_struct@@HPAPAPANHHHH@Z) Debug/mht.exe : fatal error LNK1120: 1 unresolved externals Error executing link.exe. The funcion being called in a file test.c and is defined in a file mhtwrapper.h, the code is contained in mhtwrapper.c.I have checked for all the simple mistakes that i can think of, such a spelling errors and i have tried declaring the function as external with no joy. When i run dumpbin on the mhtwrapper.obj file the function symbol does seem to be defined. Symbol index: 10 Base line number: 14 Symbol name = _mht_associate 0000001B( 15) 00000022( 16) 00000029( 17) 00000030( 20) 00000037( 22) 0000003E( 23) 00000058( 25) 00000072( 27) 00000091( 28) 00000093( 29) 00000095( 30) 000000A6( 32) 000000B5( 34) 000000C4( 35) 000000D5( 37) 000000E8( 38) 000000FB( 39) 0000010E( 41) 0000012A( 43) 00000146( 45) 00000175( 46) 000001A4( 47) 000001D3( 48) 000001D8( 49) 000001DD( 50) 000001ED( 51) 000001FF( 52) 00000211( 53) 0000021D( 54) 00000229( 55) 00000235( 58) 0000023C( 59) 0000025A( 61) 00000278( 63) 00000297( 64) 000002CB( 67) 000002DB( 69) 000002F3( 70) 0000030D( 73) 00000316( 74) 00000326( 76) 00000342( 78) 00000387( 79) 0000039F( 81) 000003EE( 82) 000003F0( 83) 000003F5( 84) 000003FA( 85) 000003FF( 86) 00000404( 87) 0000041B( 89) 00000445( 91) 0000044E( 92) 0000046C( 94) 0000047C( 95) 00000498( 98) 000004D8( 101) 00000518( 103) 00000534( 106) 0000057F( 109) 000005CA( 110) 000005CF( 111) 000005D4( 113) 000005FB( 114) 00000624( 115) 00000639( 118) 0000063E( 120) 0000064A( 123) and 010 00000000 SECT3 notype () External | _mht_associate tag index 0000001A size 0000066E lines 00000DA8 next function 00000000 Any advice would be gratly appriciated. Thanks Scott Sims Re: Simple but Painfully Annoying Tim Deveaux4-Mar-02 5:49 Tim Deveaux 4-Mar-02 5:49  Well, I had a similar problem the other day when compiling some c code with the settings (calling convention) set for __cdecl when it should have been __stdcall... (Don't laugh folks - someday one of these pitifully lame suggestions will actually help someone, and _then_ I'll be cool... ) Re: Simple but Painfully Annoying ScottS4-Mar-02 5:57 ScottS 4-Mar-02 5:57  Thanks but i have allready tried and it has no effect Scott Sims Re: Simple but Painfully Annoying Joaquín M López Muñoz4-Mar-02 7:12 Joaquín M López Muñoz 4-Mar-02 7:12  Excuse my insistence, but that name mangling thing caught my eye... is your test program file actually called test.c and not test.cpp? The compiler seems to be producing C++ code, not C. Also, the mhtwrapper.obj dump suggests that mht_associate is being compiled with extern "C" (not to be confounded with __cdecl) name decoration. If this is all obvious to you please feel free to ignore my post --but I thought it might be worth pointing out, just in case. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Simple but Painfully Annoying ScottS4-Mar-02 7:33 ScottS 4-Mar-02 7:33  I think you might be on the right track but i am a little lost, the test file was called test.cpp and not test.c which i have now changed. The change in file type seems to make no ovious difference, i still get the same error. But when i try to add the extern "C" to the decloraction of the unresolved function i get the following error, extern "C" void mht_associate(struct s1 **a, struct s2 **b, struct s3 *c, int d, double ***e, int f, int g, int h, int i); g:\work\qunetiq mht\mhtwrapper.h(11) : error C2059: syntax error : 'string' Thanks Scott Re: Simple but Painfully Annoying Joaquín M López Muñoz4-Mar-02 7:47 Joaquín M López Muñoz 4-Mar-02 7:47  OK... So you have to anwer yourself a question: Do you want the wrapper thing to work in C++ or in C? If it's the former, change everything to .cpp, forget about extern "C", and everything should be right. If it's the latter, then you might be in trouble, cause that string seems to be C++ std::string, which of course cannot be included in a C program. Anyway, this is like walking in the dark a little code would go a long way. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Simple but Painfully Annoying ScottS4-Mar-02 8:00 ScottS 4-Mar-02 8:00  I assume from what you are saying is that some code appears to be compiling as C++ and other code as C(I need platform independent pure C code) and the linker is struggling with this. So is there a compiler switch to force the compiler into pure C. Im sorry about the lack of code but unfortunatly that is unavoidable. Thanks for your time Scott Re: Simple but Painfully Annoying Joaquín M López Muñoz4-Mar-02 8:06 Joaquín M López Muñoz 4-Mar-02 8:06  OK, pure C. Then, rename everything to .c, drop every extern "C" out and do a fresh rebuild (Project -> Rebuild All.) What's the result now? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Simple but Painfully Annoying ScottS4-Mar-02 9:08 ScottS 4-Mar-02 9:08  Doing as you said had no effect but by adding \Tc to the compiler options forces pure C and i now have got the program running, thank you very much for your help it is greatly appriciated. Scott Re: Simple but Painfully Annoying Joaquín M López Muñoz4-Mar-02 9:20 Joaquín M López Muñoz 4-Mar-02 9:20  Well, you are welcome. Anyway, please note that you don't have to do anything special in VC++ to have .c files compiled as C. It is as if someone altered your VC++ settings to get the compiler to evilly treat .c files as C++. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Simple but Painfully Annoying Chris Maunder4-Mar-02 8:14 Chris Maunder 4-Mar-02 8:14  ...but we think you're cool anyway Tim. Don't we guys. guys? cheers, Chris Maunder Re: Simple but Painfully Annoying Tim Deveaux4-Mar-02 8:26 Tim Deveaux 4-Mar-02 8:26  Sure... rub it in why doncha... Re: Simple but Painfully Annoying Joaquín M López Muñoz4-Mar-02 6:11 Joaquín M López Muñoz 4-Mar-02 6:11  (Wild guess) Traces suggest C++ name mangling is in effect. Could it be you have to fix some extern "C" declarations somewhere? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo Re: Simple but Painfully Annoying ScottS4-Mar-02 6:32 ScottS 4-Mar-02 6:32  I have tried allready this with no effect, thanks anyway. Scott Sims Re: Simple but Painfully Annoying Ed Gadziemski4-Mar-02 6:25 Ed Gadziemski 4-Mar-02 6:25  You don't say if you're using MFC or WTL. If WTL, the LNK2001 error is caused when you try to do a Release build of a program that requires MSVCRT. Remove the compiler directive _ATL_MIN_CRT or remove the function call that requires the C RunTime library (malloc, printf, etc.). Re: Simple but Painfully Annoying ScottS4-Mar-02 6:31 ScottS 4-Mar-02 6:31  I am using neither, it is just a C console application and im using a debug build, i also need to use the stadard C librays throughout the program. Thanks Anyway Scott Sims Re: Simple but Painfully Annoying Ed Gadziemski4-Mar-02 8:14 Ed Gadziemski 4-Mar-02 8:14  Have you left the default setting of precompiled headers in the compile options? If so, turn it off and delete everything in your debug folder before rebuilding. Re: Simple but Painfully Annoying Kevin Smith4-Mar-02 8:38 Kevin Smith 4-Mar-02 8:38  Have you look at this link at all? http://support.microsoft.com/default.aspx?scid=kb;EN-US;q148652 does it help? need to get tenth of seconds from system time using CTime 4-Mar-02 5:20 4-Mar-02 5:20  I am using the follwing code to get the current system time and put it in HH:MM:SS format. CTime launch_event_time = CTime::GetCurrentTime(); // decompose the current time into hours minutes and seconds hours = launch_event_time.GetHour(); minutes = launch_event_time.GetMinute(); seconds = launch_event_time.GetSecond(); // format the time for display in both the track report // and geolocation tables and store in a global variable sprintf(launch_event_time_txt, "%02d:%02d:%02d", hours, minutes, seconds); What I also need is tenths of seconds. Can anyone lend a hand with this? Re: need to get tenth of seconds from system time using CTime Tim Smith4-Mar-02 5:27 Tim Smith 4-Mar-02 5:27  If I remember correctly, CTime is based on C's time_t type which doesn't support tenths of seconds. Which is just one of the many problems with time_t. Try using SYSTEMTIME or FILETIME. Tim Smith I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk? Re: need to get tenth of seconds from system time using CTime Ravi Bhavnani4-Mar-02 5:28 Ravi Bhavnani 4-Mar-02 5:28  Use getSystemTime() instead and use the wMilliseconds field of the SYSTEMTIME struct to get tenths of a second. /ravi "There is always one more bug..." http://www.ravib.com ravib@ravib.com Focus problem on windows 2000 4-Mar-02 4:47 4-Mar-02 4:47  I have a lot of problem (especially on windows 2000) to set focus input to the window I want in a multithread context (several threads manage windows) I have found this remark in an MSDN article concerning SetForegroundWindow function : Windows NT 5.0 and later: An application cannot force a window to the foreground while the user is working with another window. Instead, SetForegroundWindow will activate the window (see SetActiveWindow) and call theFlashWindowEx function to notify the user. Is somebody can explain me what "while the user is working with another window" means exactly or where I can find it

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