jdbruijn/LedCube

Convert code to the C99 standard

Opened this issue · 1 comments

Deleted user commented

Background info

Currently the XC16 compiler in MPLAB X standard uses the C89 standard. However it is possible with the -std=c99 option to use the C99 standard. Although this is still quite an old standard is has some 'new' features that could come in handy.

Step 1

Make/find a list of the new features. This will result in a list of features that should be changed in the code.

  • for (int i = 0; i < 99; ++i) { ... } instead of having the declaration of i outside the for loop;
  • ???

Step 2

Update the code in the files below to the 'new' standard.

  • Animations/Fill.h
  • Animations/src/Fill.c
  • CubeControl/Colours.h
  • CubeControl/CubeControlData.h
  • CubeControl/LayerControl.h
  • CubeControl/LedCube.h
  • CubeControl/LedDriver.h
  • CubeControl/PanelControl.h
  • CubeControl/src/CubeControlData.c
  • CubeControl/src/LayerControl.c
  • CubeControl/src/LedCube.c
  • CubeControl/src/LedDriver.c
  • CubeControl/src/PanelControl.c
  • LibraryFiles/BitOperations.h
  • LibraryFiles/Buzzer.h
  • LibraryFiles/Debug.h
  • LibraryFiles/Delay.h
  • getPICConfigurationBits.h
  • LibraryFiles/Interrupts.h
  • LibraryFiles/IOPorts.h
  • LibraryFiles/Macro.h
  • LibraryFiles/MyAssert.h
  • LibraryFiles/PeripheralPinSelect.h
  • LibraryFiles/Ports.h
  • LibraryFiles/SwFifoBuffer.h
  • LibraryFiles/System.h
  • LibraryFiles/Uart.h
  • LibraryFiles/src/BitOperations.c
  • LibraryFiles/src/Buzzer.c
  • LibraryFiles/src/getPICConfigurationBits.c
  • LibraryFiles/src/IOPorts.c
  • LibraryFiles/src/SwFifoBuffer.c
  • LibraryFiles/src/System.c
  • LibraryFiles/src/Uart.c
  • src/main.c
  • Visualisation/LedCubeVisualisation.h
  • Visualisation/src/LedCubeVisualisation.c
  • version.h

Step 3

Informative announcement:
Make clear, in the wiki or somewhere else, that the C99 standard is used for programming.

Deleted user commented

The XC16 compiler in MPLAB X uses a weird kind of c standard. When not adding the -std=c99 it is surely using the C89 standard according to the __STDC__ and __STDC_VERSION__ defines. But however in C89 it is not allowed to comment a line of code using '//', which is possible using the XC16 compiler. And for example vars can be declared anywhere in a block which should not be possible using the standard C89.
So far I could only come up with the already stated difference about the int in a for loop.
Source: http://std.dkuug.dk/JTC1/SC22/WG14/www/C99RationaleV5.10.pdf

Up-to-date list of features to change:

  • for (int i = 0; i < 99; ++i) { ... } instead of having the declaration of i outside the for loop;
  • Usage of __VA_ARGS__ in macro expanstions (p. 101);
  • %hh and %ll in printf functions are allowed (p. 152);
  • snprintf new function (p. 154);
#ifdef DEBUG
#define dfprintf(stream, ...) \   
 fprintf(stream, "DEBUG: " _ _VA_ARGS_ _)
#else
#define dfprintf(stream, ...) ((stream, _ _VA_ARGS_ _, 0))
#endif
#define dprintf(...) dfprintf(stderr, _ _VA_ARGS_ _)
For example,
dprintf("X = %d\n", x);
expands to
dfprintf(stderr, "X = %d\n", x);
and thus to one of 
Language
102
fprintf(stderr, "DEBUG: " "X = %d\n", x);
or
((stderr, "X = %d\n", x, 0));

Progress

Found that libpic30.h is not compatible with the C99 standard
c:\program files (x86)\microchip\xc16\v1.25\bin\bin\../..\support\generic\h/libpic30.h:221:34: error: expected ')' before 'void'
And the asm instruction is not supported as it seems.
Edit:
Those instructions are supported using -std=gnu99 instead of c99.