The Gay Bean posted:

I think I'm just going to start making Cmake compile all of my dependencies with specific flags and git/svn versions.. would anybody hate me if I were their coworker?

The Gay Bean posted:

I think I'm just going to start making Cmake compile all of my dependencies with specific flags and git/svn versions.. would anybody hate me if I were their coworker?

Pixelated posted:

What am I missing?

TheFreshmanWIT posted:

code:

P1OUT |= ( BIT5);

I might be reading it wrong, but it looks like the line above will not turn the light OFF when the temp is below 2+ the starting value, it'll actually just cycle it every time, right? It'll appear ON, but be turning on/off very rapidly.

Pixelated posted:

It needs to be a 1 to turn the LED on.

Pixelated posted:

Stupid embedded question that's kicking my rear end on a lab assignment with a TI Launchpad. (MSP430G2553)

I know this isn't the homework help forum, but i figured it was worth a shot to get a fresh perspective on this...

The problem is to read from a temperature sensor (TMP36GZ) and turn on an LED on port 1.5 when the temperature rises above 2 degrees Fahrenheit from the temperature recorded at startup. Conversion to Fahrenheit needs to be done by calling a function. The TA's in charge of the lab already wrote the setup for the 10 bit ADC, we just have to fill in the rest. I cannot for the life of me get this to do anything other than sit there with the LED shining with no way to change it. I verified all of the wiring so it has to be a code problem.

code:

void ConvertToF(void)
{
	/* converting from 10-bit ADC value to a fahrenheit temperature;
	* This is assuming a 3.3V Vcc*/
	tempF = ((9.0/5.0)*((((temp) * (3300.0/1024.0))-500.0)/10.0)+32.0);
}

What am I missing?

GrumpyDoctor posted:

I'm looking at a codebase that routinely calls function pointers with the wrong number of arguments. It compiles as C, but not as C++. Is there some legitimate reason for this to compile?

FamDav posted:

are the function pointers of the form T()? in c a function of that form can take as many arguments as you would like to supply to it, whereas in c++ that is explicitly a function that takes no arguments.

otherwise, you're gonna have to cast function pointers which means undefined behavior. i would think in that case youd be seeing runtime errors, though.

GrumpyDoctor posted:

Yep, that's it. My problem is that I need to compile this as C++ and they're relying on this behavior all over the place.

FamDav posted:

i honestly havent had to actually do this in the wild, but here's my understanding of how to get this done. i'm assuming this is a library? if so:

* compile the library via your c compiler
* wherever you are including headers from the c lib, wrap the macros in "extern "C" { #include "butts.h" }". this is where you find out if they were doing this in their headers :[.
* compile and link the rest of your program with your c++ compiler

if all goes correctly, your c code is compiled correctly, your c++ code calls into it with the correct calling conventions, and everybody ends up happy.

FamDav posted:

are the function pointers of the form T()? in c a function of that form can take as many arguments as you would like to supply to it, whereas in c++ that is explicitly a function that takes no arguments.

otherwise, you're gonna have to cast function pointers which means undefined behavior. i would think in that case youd be seeing runtime errors, though.

Zerilan posted:

Trying to relearn some C (my previous background in it was real basic to begin with) because my professor for my math undergrad capstone wants to use the C99 standard for part of it.

I'm trying to make a C function that can take a mathematical vector function as the 3 separate components, ie: Vector-A = <Ax,Ay,Az> where each of those 3 are 3-variable mathematic functions that can get pretty complex. I don't really know though how I should handle the function inputs so that they can be parsed as a mathematical expression that calculations can be done on where x, y, z are all arrays of values.

FamDav posted:

* wherever you are including headers from the c lib, wrap the macros in "extern "C" { #include "butts.h" }". this is where you find out if they were doing this in their headers :[.

GrumpyDoctor posted:

I know how to link C and C++ code. I want to compile it as C++ so I can include it in a mixed-mode C++/CLI assembly.

Qwertycoatl posted:

It's okay to cast function pointers to other kinds of function pointers, so long as you never call the function through a pointer of the wrong type. So when you actually want to call the function, you can cast it to the correct type just before you use it:

GrumpyDoctor posted:

I'm looking at a codebase that routinely calls function pointers with the wrong number of arguments. It compiles as C, but not as C++. Is there some legitimate reason for this to compile?

rjmccall posted:

Never do this.


There's no way to get the behavior you want in C++ without source changes, but you can certainly follow this sage advice:


You can write a variadic template to automate casting to the right function type, although I don't know if the C++/CLI frontend supports those. But you'll still need to modify both the original declaration and the definition to use C linkage, because parameter types distinguish functions in C++.

But you will probably be happier if you just bite the bullet and bring that source base kicking and screaming into the late 1980s by using proper function prototypes. Fortunately, that should be extremely scriptable.

GrumpyDoctor posted:

C code:

typedef struct {
	char  *funame;			/* function name */
	int  flags;			/* type flags */
#ifdef FUN_ARGLIST
	int  (*funp)(FUN_ARGLIST);	/* pointer to function */
#else
	int  (*funp)();			/* pointer to function */
#endif
}  FUN;

Whatever you want to argue about where that falls on the clever-horror scale, FUN_ARGLIST is never defined anywhere, and they just rely on this behavior of argumentless function pointers to make everything work. (And this particular struct isn't the only place this comes up.)

sarehu posted:

Point of order: You keep saying "vector" in places where you mean "vector field". (e: And I assume by "each R->R component" you mean "each R->R^3 component".)

Presumably you would have your function prototype be

return_type do_curl_stuff(vec3 (*vectorA)(vec3), ...other parameters...)

where vec3 is your 3 dimensional vector type, defined by something such as typedef struct { double x, y, z; } vec3; or typedef struct { double coords[3]; } vec3;.

GrumpyDoctor posted:

hackbunny posted:

Have you tried compiling the library as a native static library, and then linking to it?

Zerilan posted:

By each component I think I meant R^3->R

GrumpyDoctor posted:

Another question: Why does this

C code:

#ifdef _WIN32
extern double	erf(double x);
extern double	erfc(double x);
#endif

emit an "inconsistent dll linkage" warning for each declaration? I'm compiling as a static library.

GrumpyDoctor posted:

Another question: Why does this

C code:

#ifdef _WIN32
extern double	erf(double x);
extern double	erfc(double x);
#endif

emit an "inconsistent dll linkage" warning for each declaration? I'm compiling as a static library.

pseudorandom name posted:

Which are normally used at global or static scope in source files, not headers, but will probably work fine in this homework instance.