I get an error message when I try to build my program:
E:\Temp\ccIyLSlA.ltrans0.ltrans.o: In function main': <artificial>:(.text.startup+0x738): relocation truncated to fit: R_AVR_7_PCREL against no symbol’
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\megaatmega2560\firmware.elf] Error 1
I’ve found a “solution” but I don’t know if it’s applicable to PlatformIO !
I’m with an Arduino Mega 2560.
I got this error when I run this:
for(int i = 2; i >= 0; i --)
{
receivedChar = HC12.read();
if(isDigit(receivedChar))
{
module_id += (receivedChar-‘0’) * pow(10, i);
}
else
{ //Serial.print(“This character is not a digit: “); //Serial.print(receivedChar); //Serial.print(” (0x”); //Serial.print(receivedChar, HEX); //Serial.println(“)”);
isWrongFormat = true;
}
}
But it compiles fine when I uncoment Serial.print lines
It’s not the full program because my program has 400 lines, and I don’t know if we can reproduce it with a little script…
Thanks !
(Another request: Will you support Debugging for Arduino Mega 2560 ?)
The problem is that you’re calling in lib-math code with the pow() function which cause the linker to take some symbols from libgcc and not libm, and that code exhibits the error.
The presented workaround is to change the order of the linker flags to make libm be loaded first after libgcc.
Why -mrelax doesn’t work is beyond me. Maybe it’s a really old compiler version and you need
build_unflags = -mshort-calls
Anyway for your code I would highly suggest to not call into pow(). Since i only every has values from 2 to 0, you can just hardcode the result of the pow() call to 100, 10 and 1.
const int pow_res[3] = { 1, 10, 100};
for(int i = 2; i >= 0; i --)
{
receivedChar = HC12.read();
if(isDigit(receivedChar))
{
module_id += (receivedChar-'0') * pow_res[i];
}
else
{
//Serial.print(“This character is not a digit: “);
//Serial.print(receivedChar);
//Serial.print(” (0x”);
//Serial.print(receivedChar, HEX);
//Serial.println(")");
isWrongFormat = true;
}
}
