Thread: Different types for function parameter - how?

I've been getting two types of warnings that are starting to bother me. The most common of which is with my "LoadFile" function. I'm seeing this warning a lot and it's bogging down the list of warnings making it hard to search for where syntax errors are occurring. Thing is, I don't understand what the warning means (the ending part in particular).

Code:

char LoadFile(const char FileName[64], char FileType, BITMAPINFOHEADER *BMPInfo, 
              unsigned char *BMPData, char FogUsed, double ObjectScaling, 
              char LoadType)
...
LoadFile("HillsBG.tga", 2, &HillsInfo, &HillsData, 1, Hills.Scaling, 0);

That's the function header and how it's called. This is the warning I'm getting, taking up about half of the list of warnings I've got:

c:\my documents\my programs\interactive animation\interactive animation\interactive animation.c(1779) : warning C4047: 'function' : 'unsigned char *' differs in levels of indirection from 'unsigned char (*__w64 )[163840]'
c:\my documents\my programs\interactive animation\interactive animation\interactive animation.c(1779) : warning C4024: 'LoadFile' : different types for formal and actual parameter 4

The one referenced is the HillsData (when called) and BMPData (in the function parameter list). The BMPData is an array of a variable size. The image is 1024x40 and 32-bit color so the image data uses 163840 bytes, the reason for that array size. The mountains are 1024x128 and 32-bit color and thus use 524,288 as the array length. The sky is 640x240 and 24-bit color so it has 460,800. In other words, it's all over the place. What does this warning mean? I understand the "unsigned char *" part of it (a pointer to an unsigned char type), but what about the "unsigned char (*__w64 )[163840]" part? How do I fix this?

The other warnings occur every time I use strcpy, sprintf, and some other common C things. This warning is:

c:\my documents\my programs\interactive animation\interactive animation\interactive animation.c(1130) : warning C4996: 'sprintf' was declared deprecated
c:\program files\microsoft visual studio 8\vc\include\stdio.h(345) : see declaration of 'sprintf'
Message: 'This function or variable may be unsafe. Consider using sprintf_s instead. To disable deprecation, use _CRT_SECURE_NO_DEPRECATE. See online help for details.'

What is wrong with using strcpy or sprintf? Why is it deprecated? These types of things take up about 2/5 of the warnings, most of which from using sprintf.

Ignoring these, I have very few warnings - only 5. Otherwise, I have 67 at the moment (!).

The one thing you missed was the actual declarations of those variables -- it's an important piece of information. Since it sounds like true arrays, then the & is extraneous.

Code:

LoadFile("HillsBG.tga", 2, &HillsInfo, &HillsData, 1, Hills.Scaling, 0);

Same location; but the wrong type.

What is wrong with using strcpy or sprintf? Why is it deprecated? These types of things take up about 2/5 of the warnings, most of which from using sprintf.

They can be used in unsafe ways; Microsoft tries to get you to use their non-standard stuff instead.

Consider snprintf as a replacement for sprintf, or follow the warnings' instructions to get rid of them.

Yes. On that one did you remove the & from the call? Did the warning go away?

[edit]

Code:

LoadFile("HillsBG.tga", 2, &HillsInfo, HillsData, 1, Hills.Scaling, 0);

Wow! I had more instances than I thought. I removed that & from the call and from 67 warnings, it dropped down to just 23 (that's almost 1/3 the original)! Why are strcpy, fopen, sprintf, etc. unsafe?

Another warning I'm confused about, this one not making any sense.

c:\my documents\my programs\interactive animation\interactive animation\interactive animation.c(372) : warning C4244: '=' : conversion from 'double' to 'float', possible loss of data

There are many instances of this, but the odd part is that nothing in the area uses a double. This is line 372, the one in question:

Code:

// locals, for reference (in the LoadFile function)
	float NewColor = 0;
	float FogIntensity = (float)ObjectScaling;
	float FogRange = (float)visibility;

   NewColor = (((float)FogColor[0]*FogIntensity+(float)BMPData[ArrayIndex]
                *(FogRange-FogIntensity))/FogRange)+0.5; // fog formula

Visibility is a double as well as ObjectScaling. They are type casted to a float though so why is the warning present here?

Originally Posted by ulillillia

Why are strcpy, fopen, sprintf, etc. unsafe?

You can write beyond the size of the receiving string using strcpy and sprintf.

Originally Posted by ulillillia

Another warning I'm confused about, this one not making any sense.



There are many instances of this, but the odd part is that nothing in the area uses a double. This is line 372, the one in question:

Code:

// locals, for reference (in the LoadFile function)
	float NewColor = 0;
	float FogIntensity = (float)ObjectScaling;
	float FogRange = (float)visibility;

   NewColor = (((float)FogColor[0]*FogIntensity+(float)BMPData[ArrayIndex]
                *(FogRange-FogIntensity))/FogRange)+0.5; // fog formula

Visibility is a double as well as ObjectScaling. They are type casted to a float though so why is the warning present here?

0.5 is a double, 0.5F is a float.