How to draw a line with COCOS2D-iPhone

@implementation MyLayer
-(id)init{
 self = [super init];
 if(self != nil){
 glColor4f(0.8, 1.0, 0.76, 1.0); 
 glLineWidth(2.0f);
 CocosNode *line = drawLine(10.0f, 100.0f,400.0f,27.0f) ;
 [self addChild:line z:1];
 }
 return self;
}
@end

-(id)init{
 self = [super init];
 if(self != nil){
 glColor4f(0.8, 1.0, 0.76, 1.0); 
 glLineWidth(2.0f);
 drawLine(10.0f, 100.0f,400.0f,27.0f);< br /> }
 return self;
}

- (void)draw {
 // ...

 // draw a simple line
 // The default state is:
 // Line Width: 1
 // color: 255,255,255,255 (white, non-transparent)
 // Anti-Aliased
 glEnable(GL_LINE_SMOOTH);
 ccDrawLine( ccp(0, 0), ccp(s.width, s.height) );

 // ...
}

I tried to complete Simple things to master Cocos2d. At this point, I have a scene, and that scene has a background sprite and a layer. I tried to draw the layer with drawLine. This is my current attempt.

@implementation MyLayer
-(id)init{
 self = [super init];
 if(self != nil){
 glColor4f(0.8, 1.0, 0.76, 1.0); 
 glLineWidth(2.0f);
 CocosNode *line = drawLine(10.0f, 100.0f,400.0f,27.0f) ;
 [self addChild:line z:1];
 }
 return self;
}
@end

This will produce an error ” void value not ignored as it should be”. So obviously I did something wrong, but hope you can see my reasoning.

I tried it too

-(id)init{
 self = [super init];
 if(self != nil){
 glColor4f(0.8, 1.0, 0.76, 1.0); 
 glLineWidth(2.0f);
 drawLine(10.0f, 100.0f,400.0f,27.0f);< br /> }
 return self;
}

Which doesn’t give me an error, but it doesn’t work either. I realize that I don’t understand some fundamental things, but can anyone guide me in the right direction?

From cocos2d drawPrimitivesTest.m:

- (void)draw {
 // ...

 // draw a simple line
 // The default state is:
 // Line Width: 1
 // color: 255,255,255,255 (white, non-transparent)
 // Anti-Aliased
 glEnable(GL_LINE_SMOOTH);
 ccDrawLine( ccp(0, 0), ccp(s.width, s.height) ); 

 // ...
}