What is the execution charset with which Linux is compiled?

tinkerbeast · 01-22-2020, 10:30 PM

I know that the -fexec-charset=charset flag for compiled Linux systems will probably be the default UTF-8. My question is: How do I verify that? Is there some /proc variable which will tell me that?

The rationale behind my question is that system calls which take char * as a parameter expect the encoding to be in the same format as the compiled kernel. The safest way would be to use the kernel provided variable as a parameter for compiling an application doing system calls.

Note that this is independent of the system locale.

Added sample program to illustrate the isssue:

Code:

const char * file_name = "/tmp/有難う.txt";

int main(void) {
    if (open(file_name, 0) < 0) {
        perror("failed to open file");
    } else {
        perror("opened file");
    }
    return 0;
}

Code:

$ touch /tmp/有難う.txt
$ gcc -fexec-charset=UTF-8 source.c && ./a.out
opened file: Success
$ gcc -fexec-charset=UTF-16 source.c && ./a.out
��f: No such file or directory

elucches · 02-05-2020, 05:18 PM

I believe

Code:

man nl_langinfo

may give you the answer.
Briefly:

Code:

#include <langinfo.h>
#include <locale.h>
...
   setlocale(LC_CTYPE, "");
   printf("%s\n", nl_langinfo(CODESET));

I guess in your case it would not be printf but saving into a variable.