How do I use mblen()?
c, multibyte-functions
Solution
Turning my comment into an answer.
The details might depend on your exact execution environment, but I think the following should apply for most *NIX-systems.
`mblen` depends on the current locale
The behavior of this function is affected by the LC_CTYPE category of the current locale
The default locale on startup is the "C" locale (see `setlocale`), which might not match what you're expecting. Conveniently you can call `setlocale(LC_CTYPE, "")` to set the locale to the "native" environment.
Note that calling `setlocale(LC_ALL, "")` (as I originally wrote) changes more that you're possibly expecting, so be sure to read up on all things locale-related before doing that.
Problem
Here is some test code to help me understand multibyte character management. ``` #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char *argv[]) { char * line = malloc(1024); size_t n; getline(&line, &n, stdin); while (*line) { int offset = mblen(line, strlen(line)); if (offset == -1) return 0; printf("%d\n", offset); line += offset; } return 0; } ``` As I understand it, if the user were to type "éléphant", my output should show 2 1 2 1 ... However, it shows -1 for an `mblen` error, right from the first byte. I gather it probably ain't a bug in these 2 lines of code, what must I do, what resources can I read to get a hint on what happens here? Of course a `printf("%s", line)` would work (and does) work perfectly.