Hi! I've try to compile my code use i2c keypad with chio pcf8574 library which can be download here https://github.com/joeyoung/arduino_keypads/tree/master/Keypad_I2C

after install library and try to compile in visual studio I got error as below

C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-g++ -c -g -Os -fno-exceptions -ffunction-sections -fdata-sections -Wall -mmcu=atmega328p -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=106 -I"C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino" -I"C:\Program Files (x86)\Arduino\hardware\arduino\variants\standard" -I"C:\Program Files (x86)\Arduino\libraries\EEPROM" -I"C:\Program Files (x86)\Arduino\libraries\PS2Keyboard" -I"C:\Program Files (x86)\Arduino\libraries\Wire" -I"C:\Program Files (x86)\Arduino\libraries\Keypad_I2C" -I"C:\Program Files (x86)\Arduino\libraries" -I"C:\Program Files (x86)\Arduino\hardware\arduino\libraries" -I"C:\Program Files (x86)\Visual Micro\Visual Micro for Arduino\Micro Platforms\default\debuggers" -I"C:\Users\Tikki\Documents\Arduino\libraries" -o Led.cpp.o"  Led.cpp"  -DVISUALMICRO_COMPILER_VER=1
C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-gcc -Os -Wl,--gc-sections -mmcu=atmega328p -L"C:\Users\Tikki\AppData\Local\VMicro\Arduino\Builds\ChingSignboard\uno" -o board.elf" board.cpp.o" Led.cpp.o" PROM.cpp.o" rd\PS2Keyboard.cpp.o" .cpp.o" ity\twi.c.o" C\Keypad_I2C.cpp.o" "C:\Users\Tikki\AppData\Local\VMicro\Arduino\Builds\ChingSignboard\uno\core.a" -lm
ChingSignboard.cpp.o:In function `Keypad_I2C'
Keypad_I2C.h:Keypad(char*, unsigned char*, unsigned char*, unsigned char, unsigned char)'
Keypad_I2C.cpp.o:In function `Keypad_I2C::begin(char*)'
Keypad_I2C.cpp:begin(char*)'
Error creating .elf
 

I use arduino pro mini and if i cut this i2c keypad code off everything else is can be compile just fine. any idea?

Hi,
I've try to compile in Arduino Ide as you suggested and it seem this error came from KeypadI2C Library ,Sorry for such a waste post. I'm still a beginner in arduino so I've not sure this error cause from the code or vismicro  but now I get it, Anyway thank for your reply

regard
Tikki

Hi again, 
I like to update, Perhaps it might useful for some one who went to the same problem as me. 
I've take a look to wire.h and keypadI2C.h  like you said and found nothing wrong with it. 
so I went back to github where I download the code from and take a look in readme file. 
I've notice that the author recommend to include keypad.h in sketch  which I didn't, I've be able to compile with no error now. Thank again for you help.

regard 
Tikki