Datasheet

simply add const before the variable name:

const char str[] = "My very long string";

That string is now in FLASH. You can manipulate the string just like RAM data, the compiler

will automatically read from FLASH so you dont need special progmem-knowledgeable

functions.

You can verify where data is stored by printing out the address:

Serial.print("Address of str $"); Serial.println((int)&str, HEX);

If the address is $2000000 or larger, its in SRAM. If the address is between $0000 and

$3FFFF Then it is in FLASH