esp8266/Arduino

Arduino IDE for ESP8266

Clemens Kirchgatterer

@everslick

great. thank you very much

Me No Dev

@me-no-dev

thanbks for asking for it :D we should have added this long time ago

Mehrdad K

@mkeyno

hi @igrr are you there

is anyone hear

I really appreciated if any one could help me about the casting issue

virtual size_t fs::File::readBytes(char*, size_t) define in FS class of

I have problem to use readBytes for reading the byte type

f.readBytes( ((byte*)leds) + i, 144);

Mehrdad K

@mkeyno

where should I recasting the variable

Ivan Grokhotkov

@igrr

how is leds variable defined?

Mehrdad K

@mkeyno

this is object form fastLED lib CRGB leds[144];

consist of 3 byte R,G,B

Ivan Grokhotkov

@igrr

what is i?

Mehrdad K

@mkeyno

the location

actually this is the code line i += FILe.readBytes( ((byte*)leds) + i, (NUM_LEDS*3)-i);

it supposed to read one 144*3 byte of data from file and fed it to the LED array to display

the compiler says , I should casted to char

Ivan Grokhotkov

@igrr

can you please paste the actual error compiler produces?

Mehrdad K

@mkeyno

invalid conversion from 'byte {aka unsigned char}' to 'char*' [-fpermissive]

            i += FILe.readBytes( ((byte*)leds) + i, (NUM_LEDS*3)-i);

Ivan Grokhotkov

@igrr

okay

Mehrdad K

@mkeyno

should I override it

Ivan Grokhotkov

@igrr

so you have found the declaration of readBytes function, right?
virtual size_t fs::File::readBytes(char*, size_t)

Mehrdad K

@mkeyno

yes

Ivan Grokhotkov

@igrr

what type does it take as its first argument?

Mehrdad K

@mkeyno

I need byte for each R, G,B color

Ivan Grokhotkov

@igrr

what type does readBytes function take as its first argument?

Mehrdad K

@mkeyno

GRGB type , this is object from fastLED repo

Ivan Grokhotkov

@igrr

incorrect :)

look at readBytes function prototype again

Mehrdad K

@mkeyno

I know , but it work with char , and used many times in fastLED to read bytes

I don't know how but its work if casted to char

Ivan Grokhotkov

@igrr

so which type do you need to pass into this function if it takes char*?

Mehrdad K

@mkeyno

byte*

FILe.readBytes( ((char*)leds) + i, (NUM_LEDS*3)-i); this worked

Ivan Grokhotkov

@igrr

nope, look at the function prototype again :)

virtual size_t fs::File::readBytes(char*, size_t)

which type does it take?

Mehrdad K

@mkeyno

whereas define CRGB leds[NUM_LEDS];

Ivan Grokhotkov

@igrr

virtual size_t fs::File::readBytes(char*, size_t)
it takes char*

so you should cast to char*

Mehrdad K

@mkeyno

can I override it to byte

Ivan Grokhotkov

@igrr

just cast to char*

Mehrdad K

@mkeyno

but people use this function in FastLED repo to read bytes of data and fed it to LED.show() function

why can't override it to byte

FWeinb

@FWeinb

As far as I can see in the documentation they do cast it to (char*). See this.

Ivan Grokhotkov

@igrr

char is the same size as byte

Mehrdad K

@mkeyno

I know but we need all 255 range of color and char range -127 to 127

I should ask them how they do it

thanks @FWeinb I don't know whether it work or not

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