AVR GCC a scanf

[Richard Kaliciak]

Ahoj,

dakujem za odpoved.

Prave som sa v
file:///L:/Programme/WinAVR/doc/avr-libc/avr-libc-user-manual/group__avr__stdio.html#g67bae1ad3af79809fd770be392f90e21
docital nieco podobne:

----------------------------------------
By default, all the conversions described above are available except the 
floating-point conversions and the width is limited to 255 characters. 
The float-point conversion will be available in the extended version 
provided by the library libscanf_flt.a. Also in this case the width is 
not limited (exactly, it is limited to 65535 characters). To link a 
program against the extended version, use the following compiler flags 
in the link stage:

      -Wl,-u,vfscanf -lscanf_flt -lm
----------------------------------------

Richard Kaliciak


Slavomir Tomascik schrieb:
> Tak este doplnok, scanf float ako som napisal, postupuj podla 
> toho linku, prihod este libscanf_flt a do parametrov pre linker 
> dopln dalsi riadok "-Wl,-u,vfscanf". Mne uz takyto bastard beha OK.
> 	result = sscanf(buff, fmt, &f);
> 	result = sscanf("357.0", "%5f", &f);
> 	result = sscanf("357", "%d", &v);
> 	result = sscanf("357", "%d", &v);
> 	sprintf(buff,"A%5f",d);
> 	sprintf(buff,"A%d",v);
> 
> Slavo T.
> 
> 
>>Nazdar,
>>
>>   neviem, ci to uz mas vyriesene, ale ked nie...
>>Vyskusal som to u seba, a dosiel som k zaveru, ze sscanf je 
>>implementovana (funguje mi integer), a "iba" nepodporuje float. 
>>Aby bolo jasne, tak s AVR-GCC sa iba zacinam hrat ;-) Normalne 
>>totiz nefunguje ani float sprintf, a treba urobit dalsie kroky 
>>napr. podla:
>>http://winavr.scienceprog.com/avr-gcc-tutorial/using-sprintf--function-for-float-numbers-in-avr-gcc.html
>>aby si rozbehol float pre sprintf. A kedze taka ista kniznica 
>>(libscanf_flt.a) je aj pre sscanf, tak myslim, ze to bude v tom. 
>>Treba ju tam dodat, a povedat o tom linkeru. Toto este nemam.
>>
>>Slavo T.
>>
>>
>>>Dobry den,
>>>
>>>chcem sa opytat tych, co pouzivaju AVR-GCC (WinAVR), ci je 
>>>implementovana funkcia sscanf a ci funguje, pripadne kde robim chybu. 
>>>Mam takyto priklad:
>>>
>>>// needed for use of PSTR below
>>>#include <avr/pgmspace.h>
>>>#include <stdio.h>
>>>#include <stdlib.h>
>>>
>>>char PROGMEM fmt[] = "%f";
>>>
>>>int main( void ){
>>>	char buffer[20] = {"1.25"};
>>>	float flFaktor = 0.0;
>>>	int result;
>>>	
>>>	result = sscanf( buffer, "%f", &flFaktor );
>>>	flFaktor = 1.0;
>>>	result = sscanf_P( buffer, fmt, &flFaktor );
>>>	flFaktor = 2.0;
>>>	flFaktor = atof( buffer );
>>>	flFaktor = 3.0;
>>>	result = sscanf_P( buffer, PSTR( "%f" ), &flFaktor );
>>>	flFaktor = 4.0;
>>>	flFaktor = strtod( buffer, (char**)NULL );
>>>	
>>>	return 0;
>>>}
>>>
>>>Je to prelozene s "gcc version 4.2.2 (WinAVR 20071221)" v AVR studiu, s 
>>>vypnutou optimalizaciou, aby som videl vysledky:
>>>
>>>avr-gcc.exe  -mmcu=atmega128 -Wall -gdwarf-2 -std=gnu99 -O0 
>>>-funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -MD -MP 
>>>-MT test-float.o -MF dep/test-float.o.d  -c  ../test-float.c
>>>
>>>Ked ten program v simulatore krokujem, tak atof a strtod funguju 
>>>(flFaktor=1.25), ale sscanf tu hodnotu nemeni.
>>>
>>>Poradi niekto?
>>>Pripadne to vyskusajte u seba, ci vam to funguje.
>>>
>>>Richard Kaliciak