GCC and boolean ....

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AmiDARK

Posted on: 2009/2/22 11:19 #1

Quite a regular

Hi All,

I encounter a small issue using boolean.
Here is my code :

1st part, the main C project :


#include <gl/glut.h>



int argc;

char** argv;



#include "setup.c"

#include "camera.c"

#include "core.c"



int main( int argc, char** argv ){

  Constructor();

  SetDisplayMode( 640, 480 );

  Destructor();

  return 0;

 }

And now, part of setup.c file :


/* Variables globales au fichier lib */

BOOL FullSCREEN;

int WindowID;



/* Procedure d'initialisation de la lib DISPLAY */

void Constructor( void ){

  FullSCREEN = FALSE;

  glutInit( &argc, argv );                                       /* Initialize Glut */

/*  glutDisplayFunc( DisplayFunc ); */

/*  glutReshapeFunc( ReshapeFunc ); */

 }



/* Procedure de la fermeture de la librairie DISPLAY */

void Destructor( void ){

  glutDestroyWindow( WindowID );

 }



/* Cr?ation de la fen?tre d'affichage principale */

void SetDisplayMode( int Width, int Height ){                    /* TO DO : MUST ADDED WITH TO InitDisplayMode */

  /* Open the screen using windowed mode */

  glutInitDisplayMode( GLUT_DOUBLE | GLUT_RGBA );              /* Define display mode properties */

  glutInitWindowSize( Width, Height );

  glutInitWindowPosition( 32, 32 );

  WindowID == glutCreateWindow( "AmiDARK Basic application" ); /* Create the asked window */

  if (FullSCREEN = TRUE){

    glutGameModeString( "640x480:32" );

    glutEnterGameMode();

   }

 }

When I compile the main C file, it compiles correctly but, when I run it, it open a window and jump in fullscreen mode. It shouldn't jump in fullscreeen mode.
if I change in the SetDisplayMode() function, this line :


if (FullSCREEN = TRUE){

with :


if (FullSCREEN = FALSE){

then it run, open a window and quit correctly without using full screen mode...
Why does boolean act this way ? it should work as opposite than this . not ?

Kindest Regards,
Freddix

All we have to decide is what to do with the time that is given to us.

salass00

Re: GCC and boolean ....

Posted on: 2009/2/22 11:32 #2

Just can't stay away

@freddix

Quote:

if (FullSCREEN = TRUE){

This condition will always be true since you're not doing a comparison but an assigment, i.e. your code is the same as:

Quote:

FullSCREEN = TRUE;
if (FullSCREEN){

What you want to do is either:

Quote:

if (FullSCREEN == TRUE){

or simply:

Quote:

if (FullSCREEN){

AmiDARK

Re: GCC and boolean ....

Posted on: 2009/2/22 11:46 #3

Quite a regular

@salass00
Effectively,
I've re-read my C book and if comparizon need == instead of simple =.

Thank you.

All we have to decide is what to do with the time that is given to us.

thomas

Re: GCC and boolean ....

Posted on: 2009/2/22 15:16 #4

Not too shy to talk

@freddix

Quote:

if comparizon need == instead of simple =.

That's not exact. "==" is always a comparison, no matter where used and "=" is always an assignment, no matter where used. Unlike other programming languages, it is not related to "if" (or other places where conditions are used like "while" or "for").

Bye,
Thomas

AmiDARK

Re: GCC and boolean ....

Posted on: 2009/2/22 17:34 #5

Quite a regular

@thomas
Ok

Now my dev work perfectly :)
Will add new functions :p

All we have to decide is what to do with the time that is given to us.

ssolie

Re: GCC and boolean ....

Posted on: 2009/2/22 18:51 #6

Amigans Defender

@freddix
Quote:

if (FullSCREEN = TRUE)

This is of course an assignment and I would have expected the compiler to warn you if you had -Wall on or similar.

I would also say this is bad coding style.
Here are my preferences:
if (FullSCREEN == TRUE) // ok
if (FullSCREEN) // better
if (IsFullScreen) // best

ExecSG Team Lead

AmiDARK

Re: GCC and boolean ....

Posted on: 2009/2/22 19:43 #7

Quite a regular

@ssolie
Quote:

if (IsFullScreen) // best

Then you prefer IsFullScreen as bool to handle fullscreen mode state ?

All we have to decide is what to do with the time that is given to us.

MichaelMerkel

Re: GCC and boolean ....

Posted on: 2009/2/22 21:39 #8

Not too shy to talk

@freddix

Quote:

freddix wrote:
@ssolie
Quote:

if (IsFullScreen) // best

Then you prefer IsFullScreen as bool to handle fullscreen mode state ?

it is always nice to follow some "naming conventions". and a very good and easy one is to name vaiables in a way that one can see (or guess) at first sight
- the type of the variable
- the meaning of the variable
- the scope of the variable

boolean -> prefeix like "is...", "has...", ... is very intuitive.
"FullScreen" tells the use
maybe missing is the scope. global or local. or a member of a class/instance, or static, or whatever. maybe not needed for smaller programs.

just my experience from my knowledge in our company.

byebye...

Michael Merkel