Author Topic: WinAVR stdio functions problem  (Read 7431 times)

Offline Longin

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WinAVR stdio functions problem
« on: February 01, 2014, 01:35:26 pm »
Hello
This is my first post and I would like to say that I have read forum rules...so I hope u wonīt beat me for this.

Windows XP SP3, last WinAVR (20100110) and fresh installation of Code::blocks (default settings, detected toolchains etc)
Everything have worked fine until now
I have problem with using function sprintf() from stdio.h.
Example code:
Code: [Select]
#include <avr/io.h>
#include <stdio.h>
int main(void) {
    char buffer[10];
    unsigned int temp;
    sprintf( buffer, "%d", temp) ;
    while(1) ;
    return 0;
}
}

Build log:
Code: [Select]
-------------- Build: Debug in Pokus (compiler: GNU GCC Compiler for AVR)---------------

avr-gcc.exe -Wall -mmcu=atmega16 -DF_CPU=16000000UL -g -IC:\WinAVR\avr\include -c main.c -o obj\Debug\main.o
avr-g++.exe -LC:\WinAVR\avr\lib -o bin\Debug\Pokus.elf obj\Debug\main.o  -mmcu=atmega16 -Wl,-Map=bin\Debug\Pokus.map,--cref 
C:\WinAVR\avr\lib\libc.a(vfprintf_std.o): In function `vfprintf':
(.text.avr-libc+0xd4): undefined reference to `__mulhi3'
C:\WinAVR\avr\lib\libc.a(vfprintf_std.o): In function `vfprintf':
(.text.avr-libc+0xe4): undefined reference to `__mulhi3'

consulting C::B FAQ and Google I changed Linker options in Project build options to:
Code: [Select]
-Wl
-u,vfprintf
-lprintf_flt
-lm

from default:
Code: [Select]
-mmcu=atmega16
-Wl,-Map=$(TARGET_OUTPUT_DIR)$(TARGET_OUTPUT_BASENAME).map,--cref

and it "fixed" the problem.
Build log:
Code: [Select]
avr-gcc.exe -mmcu=atmega16 -Wall -DF_CPU=16000000UL -g -IC:\WinAVR\avr\include -c main.c -o obj\Debug\main.o
avr-g++.exe -LC:\WinAVR\avr\lib -o bin\Debug\Pokus.elf obj\Debug\main.o  -Wl -u,vfprintf -lprintf_flt -lm 
Output file is bin\Debug\Pokus.elf with size 5.09 KB
Running project post-build steps
cmd /c "avr-objdump -h -S bin\Debug\Pokus.elf > bin\Debug\Pokus.lss"
avr-objcopy -R .eeprom -R .fuse -R .lock -R .signature -O ihex bin\Debug\Pokus.elf bin\Debug\Pokus.hex
avr-objcopy --no-change-warnings -j .eeprom --change-section-lma .eeprom=0 -O ihex bin\Debug\Pokus.elf bin\Debug\Pokus.eep

.hex is created and program in mcu works. Itīs fine but it mess Project linker settings in C::B doesnīt it?
I always can use C::B Tool for own Makefile what works too and I have complete view over compilation/linking process but using IDE is using IDE.

Sorry for my creepy English