Difference between revisions of "Multi language C embedded"

Revision as of 09:02, 25 October 2016

Different approaches of implementing multi language support in embedded C projects. (See links below).

Design goals

• Should only exist in flash. (No copying to RAM)
• Logical for translators to translate from english to other language.
• Easy to change language on-the-fly
• No padding of strings to max length in arrays
  • In the example below the text strings yes and no use the same amount of memory as the long message.

char txt[3][] = {
  "Yes",
  "No",
  "The format received is inconsistent with RFC 1024",
};

Simple Example

In this small example both languages are in the same file. In a project, you should have a file called english.h where all your english messages should reside. When the project is internationalized send a copy of english.h to the translator with a new name. For example german.h

Remember: The translator must keep the variables as indicated by %<TYPE> in all messages.

char const * const danish[] = {
  "FEJL: Kommando eksisterer ikke: %s",
  "FEJL: Dato %s ugyldig",
  "Advarsel: Der er kun %u%% batteri tilbage!"
};
char const * const english[] = {
  "ERROR: Non-existing command: %s",
  "ERROR: Invalid Date %s",
  "Warning: Only %u%% battery left!"
};
void example(void) {
  char **textmes;
  
  textmes = (char **) &danish;  // Set danish language
  printf( textmes[2], 17);      // Outputs: Advarsel: Der er kun 17% batteri tilbage!
  textmes = (char **) &english; // Set english language
  printf( textmes[2], 17);      // Outputs: Warning: Only 17% battery left!

}