store and retrieve array of chars in flash memory

Projects Programming
20

renanlopesmister:
Well, I need to redo all my print routines so that these routines, instead of receiving an array of RAM characters as a parameter, get a byte-byte reading of the strings in flash memory, for example, and print as desired. This will be quite laborious, but my scketch is not working anyway ...

Why byte-by-byte? It's still not clear to me what you want to achieve. For simple concatenation of two strings that are stored in flash, see reply #7.

In the below, I used strcpy_P (I forgot about strcat) which will give the same result; the strings are stored in flash but the pointer array is however stored in ram.

const char hello[] PROGMEM = "Hello";
const char space[] PROGMEM = " ";
const char world[] PROGMEM = "world";

const char *texts[] =
{
  hello,
  space,
  world,
};

void foo(char *b, const char *t[], int numElements)
{
  for (int cnt = 0; cnt < numElements; cnt++)
  {
    strcpy_P(&b[strlen(b)], t[cnt]);
  }
}

void setup()
{
  Serial.begin(57600);
  char buffer[64];
  buffer[0] = '\0';
  strcpy_P(buffer, texts[0]);
  Serial.print("'"); Serial.print(buffer); Serial.println("'");
  strcpy_P(&buffer[strlen(buffer)], texts[1]);
  Serial.print("'"); Serial.print(buffer); Serial.println("'");
  strcpy_P(&buffer[strlen(buffer)], texts[2]);
  Serial.print("'"); Serial.print(buffer); Serial.println("'");

  buffer[0] = '\0';
  foo(buffer, texts, sizeof(texts) / sizeof(texts[0]));
  Serial.print("'"); Serial.print(buffer); Serial.println("'");
}

void loop()
{
}

renanlopesmister:
But why can I pass the strings, which are in flash memory, to a buffer one way and not another?

Do you mean, why can I read but not write?