Multi language C embedded
From Teknologisk videncenter
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!
}