Question

I’m using a library that unfortunately, it appears the developer no longer works on or replies to issues in his Git repository. The library is used to drive HT1632C LED matrix drivers, and while it works in 0022/0023, it does not work in Arduino 1.0. When compiled, my Sketch gives the following error:

In file included from Final_code__1_0compatible.cpp:7:
C:\arduino-1.0\libraries\ht1632c/ht1632c.h:182: error: conflicting return type specified for 'virtual void ht1632c::write(uint8_t)'
C:\arduino-1.0\hardware\arduino\cores\arduino/Print.h:48: error:   overriding 'virtual size_t Print::write(uint8_t)'

Referencing this site: http://arduino.cc/forum/index.php?topic=82450.0, I found a comment from someone who had the same compilation errors I did (but with another library). It looks like their fix was to replace something with “size_t”

Line 200: size_t write(uint8_t); //changed to resolve conflict with print.h

The conflicting lines in the library’s .h and .cpp files look to be:

.h:

void write(uint8_t chr);

.cpp:

void ht1632c::write(uint8_t chr)
{
    byte x, y;
    if (chr == '\n') {
        //y_cur += font_height;
    } else {
        //x_cur += putchar(x_cur, y_cur, chr, GREEN, PROPORTIONAL);
        //x_cur = 0;
        //y_cur = 0;
    }
    //sendframe();
}

I’m not a C/C++ expert, but am I correct, in that if I change the .h to be “size_t write(uint8_t chr)” and the .cpp to be “size_t ht1632c::write(uint8_t chr)” that this will work?

I tried doing it, and it compiles, but I don’t know if I replace the word “void” with “size_t”, or if I need to replace the “uint8_t” with “size_t”.

Answer 1

so,

size_t ht1632c::write(uint8_t chr)

is the right function change. You should also add a

return 1;

right after the

sendframe();

line. write is expected to return the number of characters successfully written, as you don’t have any way in the code as pasted to determine if there is an error in the writing, you should just say it worked.