Hi Eric,
> Would you please post your test os(linux kernel version) and which g++
> version you use, especially when you pass the test
> -------------
> #include <iostream>
> #include <fstream>
> #include <string>
> //#include <cstring>
>
> using namespace std;
> int main(int argc, char *argv[]) {
>
> /* try {
> std::locale::global(std::locale(""));
> } catch ( ... ) { }; */
>
> wstring ws2 = L"Euro: \x20ac";
> wofstream out("unicode.txt");
> if(not out.good())
> cerr << "Error opening output file" << endl;
> //const char *name = "el_GR.utf8";
> const char *name = "en_US.utf8";
> if(argc == 2)
> name = argv[1];
> cout << "trying to access locale " << name << endl;
> locale loc;
> try{
> loc = locale(name);
> cout << "Generated locale " << loc.name() << endl;
> }catch( exception &e){
> cerr << "Couldn't generate locale " << name << ": " << e.what() <<
> endl;
> }
> out.imbue(loc);
> if(not out.good())
> cerr << "Error when setting the locale" << endl;
> out << ws2<< endl;
> if(not out.good())
> cerr << "Error when writing to file" << endl;
> }
> ------------
You could try to run the test-program with "strace", like
strace ./test en_US.utf8
this tells at least what the code is trying to do while loading the
encoding. On my machine I get the following for an EXISTING encoding:
open("unicode.txt", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 3), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb8588e6000
write(1, "trying to access locale fr_FR.ut"..., 35trying to access locale fr_FR.utf8
) = 35
open("/usr/lib/locale/locale-archive", O_RDONLY) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=1527584, ...}) = 0
mmap(NULL, 1527584, PROT_READ, MAP_PRIVATE, 4, 0) = 0x7fb85875d000
close(4) = 0
open("/usr/lib/gconv/gconv-modules.cache", O_RDONLY) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=26048, ...}) = 0
mmap(NULL, 26048, PROT_READ, MAP_SHARED, 4, 0) = 0x7fb8588df000
close(4) = 0
write(1, "Generated locale fr_FR.utf8\n", 28Generated locale fr_FR.utf8
) = 28
And for a NON-EXISTING encoding (fr_FF.utf8):
open("unicode.txt", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 3), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc99aff4000
write(1, "trying to access locale fr_FF.ut"..., 35trying to access locale fr_FF.utf8
) = 35
open("/usr/lib/locale/locale-archive", O_RDONLY) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=1527584, ...}) = 0
mmap(NULL, 1527584, PROT_READ, MAP_PRIVATE, 4, 0) = 0x7fc99ae6b000
close(4) = 0
open("/usr/share/locale/locale.alias", O_RDONLY) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc99aff3000
read(4, "# Locale name alias data base.\n#"..., 4096) = 2570
read(4, "", 4096) = 0
close(4) = 0
munmap(0x7fc99aff3000, 4096) = 0
open("/usr/lib/locale/fr_FF.utf8/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/fr_FF/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/fr.utf8/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/lib/locale/fr/LC_CTYPE", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "Couldn't generate locale ", 25Couldn't generate locale ) = 25
So, I suggest for my machine:
- it searches in "/usr/lib/locale/locale-archive" for the encoding
- if it is found, it loads the encoding from "/usr/lib/gconv/gconv-modules.cache"
- if it is NOT found, it searches for related directories in
/usr/lib/locale/ , trying to open a file LC_CTYPE
If your compiler/os/standard-library has working locale-support, I would
expect it to do something similar -- if the locale-support is
deactivated in the compiler, one should see it here.
Other opinions?
Axel
