1 /* Determine a canonical name for the current locale's character encoding.
2
3 Copyright (C) 2000-2006, 2008-2017 Free Software Foundation, Inc.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License along
16 with this program; if not, see <http://www.gnu.org/licenses/>. */
17
18 /* Written by Bruno Haible <bruno@clisp.org>. */
19
20 #include <config.h>
21
22 /* Specification. */
23 #include "localcharset.h"
24
25 #include <fcntl.h>
26 #include <stddef.h>
27 #include <stdio.h>
28 #include <string.h>
29 #include <stdlib.h>
30
31 #if defined __APPLE__ && defined __MACH__ && HAVE_LANGINFO_CODESET
32 # define DARWIN7 /* Darwin 7 or newer, i.e. Mac OS X 10.3 or newer */
33 #endif
34
35 #if defined _WIN32 || defined __WIN32__
36 # define WINDOWS_NATIVE
37 # include <locale.h>
38 #endif
39
40 #if defined __EMX__
41 /* Assume EMX program runs on OS/2, even if compiled under DOS. */
42 # ifndef OS2
43 # define OS2
44 # endif
45 #endif
46
47 #if !defined WINDOWS_NATIVE
48 # include <unistd.h>
49 # if HAVE_LANGINFO_CODESET
50 # include <langinfo.h>
51 # else
52 # if 0 /* see comment below */
53 # include <locale.h>
54 # endif
55 # endif
56 # ifdef __CYGWIN__
57 # define WIN32_LEAN_AND_MEAN
58 # include <windows.h>
59 # endif
60 #elif defined WINDOWS_NATIVE
61 # define WIN32_LEAN_AND_MEAN
62 # include <windows.h>
63 #endif
64 #if defined OS2
65 # define INCL_DOS
66 # include <os2.h>
67 #endif
68
69 /* For MB_CUR_MAX_L */
70 #if defined DARWIN7
71 # include <xlocale.h>
72 #endif
73
74 #if ENABLE_RELOCATABLE
75 # include "relocatable.h"
76 #else
77 # define relocate(pathname) (pathname)
78 #endif
79
80 /* Get LIBDIR. */
81 #ifndef LIBDIR
82 # include "configmake.h"
83 #endif
84
85 /* Define O_NOFOLLOW to 0 on platforms where it does not exist. */
86 #ifndef O_NOFOLLOW
87 # define O_NOFOLLOW 0
88 #endif
89
90 #if defined _WIN32 || defined __WIN32__ || defined __CYGWIN__ || defined __EMX__ || defined __DJGPP__
91 /* Native Windows, Cygwin, OS/2, DOS */
92 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
93 #endif
94
95 #ifndef DIRECTORY_SEPARATOR
96 # define DIRECTORY_SEPARATOR '/'
97 #endif
98
99 #ifndef ISSLASH
100 # define ISSLASH(C) ((C) == DIRECTORY_SEPARATOR)
101 #endif
102
103 #if HAVE_DECL_GETC_UNLOCKED
104 # undef getc
105 # define getc getc_unlocked
106 #endif
107
108 /* The following static variable is declared 'volatile' to avoid a
109 possible multithread problem in the function get_charset_aliases. If we
110 are running in a threaded environment, and if two threads initialize
111 'charset_aliases' simultaneously, both will produce the same value,
112 and everything will be ok if the two assignments to 'charset_aliases'
113 are atomic. But I don't know what will happen if the two assignments mix. */
114 #if __STDC__ != 1
115 # define volatile /* empty */
116 #endif
117 /* Pointer to the contents of the charset.alias file, if it has already been
118 read, else NULL. Its format is:
119 ALIAS_1 '\0' CANONICAL_1 '\0' ... ALIAS_n '\0' CANONICAL_n '\0' '\0' */
120 static const char * volatile charset_aliases;
121
122 /* Return a pointer to the contents of the charset.alias file. */
123 static const char *
get_charset_aliases(void)124 get_charset_aliases (void)
125 {
126 const char *cp;
127
128 cp = charset_aliases;
129 if (cp == NULL)
130 {
131 #if !(defined DARWIN7 || defined VMS || defined WINDOWS_NATIVE || defined __CYGWIN__ || defined OS2)
132 const char *dir;
133 const char *base = "charset.alias";
134 char *file_name;
135
136 /* Make it possible to override the charset.alias location. This is
137 necessary for running the testsuite before "make install". */
138 dir = getenv ("CHARSETALIASDIR");
139 if (dir == NULL || dir[0] == '\0')
140 dir = relocate (LIBDIR);
141
142 /* Concatenate dir and base into freshly allocated file_name. */
143 {
144 size_t dir_len = strlen (dir);
145 size_t base_len = strlen (base);
146 int add_slash = (dir_len > 0 && !ISSLASH (dir[dir_len - 1]));
147 file_name = (char *) malloc (dir_len + add_slash + base_len + 1);
148 if (file_name != NULL)
149 {
150 memcpy (file_name, dir, dir_len);
151 if (add_slash)
152 file_name[dir_len] = DIRECTORY_SEPARATOR;
153 memcpy (file_name + dir_len + add_slash, base, base_len + 1);
154 }
155 }
156
157 if (file_name == NULL)
158 /* Out of memory. Treat the file as empty. */
159 cp = "";
160 else
161 {
162 int fd;
163
164 /* Open the file. Reject symbolic links on platforms that support
165 O_NOFOLLOW. This is a security feature. Without it, an attacker
166 could retrieve parts of the contents (namely, the tail of the
167 first line that starts with "* ") of an arbitrary file by placing
168 a symbolic link to that file under the name "charset.alias" in
169 some writable directory and defining the environment variable
170 CHARSETALIASDIR to point to that directory. */
171 fd = open (file_name,
172 O_RDONLY | (HAVE_WORKING_O_NOFOLLOW ? O_NOFOLLOW : 0));
173 if (fd < 0)
174 /* File not found. Treat it as empty. */
175 cp = "";
176 else
177 {
178 FILE *fp;
179
180 fp = fdopen (fd, "r");
181 if (fp == NULL)
182 {
183 /* Out of memory. Treat the file as empty. */
184 close (fd);
185 cp = "";
186 }
187 else
188 {
189 /* Parse the file's contents. */
190 char *res_ptr = NULL;
191 size_t res_size = 0;
192
193 for (;;)
194 {
195 int c;
196 char buf1[50+1];
197 char buf2[50+1];
198 size_t l1, l2;
199 char *old_res_ptr;
200
201 c = getc (fp);
202 if (c == EOF)
203 break;
204 if (c == '\n' || c == ' ' || c == '\t')
205 continue;
206 if (c == '#')
207 {
208 /* Skip comment, to end of line. */
209 do
210 c = getc (fp);
211 while (!(c == EOF || c == '\n'));
212 if (c == EOF)
213 break;
214 continue;
215 }
216 ungetc (c, fp);
217 if (fscanf (fp, "%50s %50s", buf1, buf2) < 2)
218 break;
219 l1 = strlen (buf1);
220 l2 = strlen (buf2);
221 old_res_ptr = res_ptr;
222 if (res_size == 0)
223 {
224 res_size = l1 + 1 + l2 + 1;
225 res_ptr = (char *) malloc (res_size + 1);
226 }
227 else
228 {
229 res_size += l1 + 1 + l2 + 1;
230 res_ptr = (char *) realloc (res_ptr, res_size + 1);
231 }
232 if (res_ptr == NULL)
233 {
234 /* Out of memory. */
235 res_size = 0;
236 free (old_res_ptr);
237 break;
238 }
239 strcpy (res_ptr + res_size - (l2 + 1) - (l1 + 1), buf1);
240 strcpy (res_ptr + res_size - (l2 + 1), buf2);
241 }
242 fclose (fp);
243 if (res_size == 0)
244 cp = "";
245 else
246 {
247 *(res_ptr + res_size) = '\0';
248 cp = res_ptr;
249 }
250 }
251 }
252
253 free (file_name);
254 }
255
256 #else
257
258 # if defined DARWIN7
259 /* To avoid the trouble of installing a file that is shared by many
260 GNU packages -- many packaging systems have problems with this --,
261 simply inline the aliases here. */
262 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
263 "ISO8859-2" "\0" "ISO-8859-2" "\0"
264 "ISO8859-4" "\0" "ISO-8859-4" "\0"
265 "ISO8859-5" "\0" "ISO-8859-5" "\0"
266 "ISO8859-7" "\0" "ISO-8859-7" "\0"
267 "ISO8859-9" "\0" "ISO-8859-9" "\0"
268 "ISO8859-13" "\0" "ISO-8859-13" "\0"
269 "ISO8859-15" "\0" "ISO-8859-15" "\0"
270 "KOI8-R" "\0" "KOI8-R" "\0"
271 "KOI8-U" "\0" "KOI8-U" "\0"
272 "CP866" "\0" "CP866" "\0"
273 "CP949" "\0" "CP949" "\0"
274 "CP1131" "\0" "CP1131" "\0"
275 "CP1251" "\0" "CP1251" "\0"
276 "eucCN" "\0" "GB2312" "\0"
277 "GB2312" "\0" "GB2312" "\0"
278 "eucJP" "\0" "EUC-JP" "\0"
279 "eucKR" "\0" "EUC-KR" "\0"
280 "Big5" "\0" "BIG5" "\0"
281 "Big5HKSCS" "\0" "BIG5-HKSCS" "\0"
282 "GBK" "\0" "GBK" "\0"
283 "GB18030" "\0" "GB18030" "\0"
284 "SJIS" "\0" "SHIFT_JIS" "\0"
285 "ARMSCII-8" "\0" "ARMSCII-8" "\0"
286 "PT154" "\0" "PT154" "\0"
287 /*"ISCII-DEV" "\0" "?" "\0"*/
288 "*" "\0" "UTF-8" "\0";
289 # endif
290
291 # if defined VMS
292 /* To avoid the troubles of an extra file charset.alias_vms in the
293 sources of many GNU packages, simply inline the aliases here. */
294 /* The list of encodings is taken from the OpenVMS 7.3-1 documentation
295 "Compaq C Run-Time Library Reference Manual for OpenVMS systems"
296 section 10.7 "Handling Different Character Sets". */
297 cp = "ISO8859-1" "\0" "ISO-8859-1" "\0"
298 "ISO8859-2" "\0" "ISO-8859-2" "\0"
299 "ISO8859-5" "\0" "ISO-8859-5" "\0"
300 "ISO8859-7" "\0" "ISO-8859-7" "\0"
301 "ISO8859-8" "\0" "ISO-8859-8" "\0"
302 "ISO8859-9" "\0" "ISO-8859-9" "\0"
303 /* Japanese */
304 "eucJP" "\0" "EUC-JP" "\0"
305 "SJIS" "\0" "SHIFT_JIS" "\0"
306 "DECKANJI" "\0" "DEC-KANJI" "\0"
307 "SDECKANJI" "\0" "EUC-JP" "\0"
308 /* Chinese */
309 "eucTW" "\0" "EUC-TW" "\0"
310 "DECHANYU" "\0" "DEC-HANYU" "\0"
311 "DECHANZI" "\0" "GB2312" "\0"
312 /* Korean */
313 "DECKOREAN" "\0" "EUC-KR" "\0";
314 # endif
315
316 # if defined WINDOWS_NATIVE || defined __CYGWIN__
317 /* To avoid the troubles of installing a separate file in the same
318 directory as the DLL and of retrieving the DLL's directory at
319 runtime, simply inline the aliases here. */
320
321 cp = "CP936" "\0" "GBK" "\0"
322 "CP1361" "\0" "JOHAB" "\0"
323 "CP20127" "\0" "ASCII" "\0"
324 "CP20866" "\0" "KOI8-R" "\0"
325 "CP20936" "\0" "GB2312" "\0"
326 "CP21866" "\0" "KOI8-RU" "\0"
327 "CP28591" "\0" "ISO-8859-1" "\0"
328 "CP28592" "\0" "ISO-8859-2" "\0"
329 "CP28593" "\0" "ISO-8859-3" "\0"
330 "CP28594" "\0" "ISO-8859-4" "\0"
331 "CP28595" "\0" "ISO-8859-5" "\0"
332 "CP28596" "\0" "ISO-8859-6" "\0"
333 "CP28597" "\0" "ISO-8859-7" "\0"
334 "CP28598" "\0" "ISO-8859-8" "\0"
335 "CP28599" "\0" "ISO-8859-9" "\0"
336 "CP28605" "\0" "ISO-8859-15" "\0"
337 "CP38598" "\0" "ISO-8859-8" "\0"
338 "CP51932" "\0" "EUC-JP" "\0"
339 "CP51936" "\0" "GB2312" "\0"
340 "CP51949" "\0" "EUC-KR" "\0"
341 "CP51950" "\0" "EUC-TW" "\0"
342 "CP54936" "\0" "GB18030" "\0"
343 "CP65001" "\0" "UTF-8" "\0";
344 # endif
345 # if defined OS2
346 /* To avoid the troubles of installing a separate file in the same
347 directory as the DLL and of retrieving the DLL's directory at
348 runtime, simply inline the aliases here. */
349
350 /* The list of encodings is taken from "List of OS/2 Codepages"
351 by Alex Taylor:
352 <http://altsan.org/os2/toolkits/uls/index.html#codepages>.
353 See also "IBM Globalization - Code page identifiers":
354 <http://www-01.ibm.com/software/globalization/cp/cp_cpgid.html>. */
355 cp = "CP813" "\0" "ISO-8859-7" "\0"
356 "CP878" "\0" "KOI8-R" "\0"
357 "CP819" "\0" "ISO-8859-1" "\0"
358 "CP912" "\0" "ISO-8859-2" "\0"
359 "CP913" "\0" "ISO-8859-3" "\0"
360 "CP914" "\0" "ISO-8859-4" "\0"
361 "CP915" "\0" "ISO-8859-5" "\0"
362 "CP916" "\0" "ISO-8859-8" "\0"
363 "CP920" "\0" "ISO-8859-9" "\0"
364 "CP921" "\0" "ISO-8859-13" "\0"
365 "CP923" "\0" "ISO-8859-15" "\0"
366 "CP954" "\0" "EUC-JP" "\0"
367 "CP964" "\0" "EUC-TW" "\0"
368 "CP970" "\0" "EUC-KR" "\0"
369 "CP1089" "\0" "ISO-8859-6" "\0"
370 "CP1208" "\0" "UTF-8" "\0"
371 "CP1381" "\0" "GB2312" "\0"
372 "CP1386" "\0" "GBK" "\0"
373 "CP3372" "\0" "EUC-JP" "\0";
374 # endif
375 #endif
376
377 charset_aliases = cp;
378 }
379
380 return cp;
381 }
382
383 /* Determine the current locale's character encoding, and canonicalize it
384 into one of the canonical names listed in config.charset.
385 The result must not be freed; it is statically allocated.
386 If the canonical name cannot be determined, the result is a non-canonical
387 name. */
388
389 #ifdef STATIC
390 STATIC
391 #endif
392 const char *
locale_charset(void)393 locale_charset (void)
394 {
395 const char *codeset;
396 const char *aliases;
397
398 #if !(defined WINDOWS_NATIVE || defined OS2)
399
400 # if HAVE_LANGINFO_CODESET
401
402 /* Most systems support nl_langinfo (CODESET) nowadays. */
403 codeset = nl_langinfo (CODESET);
404
405 # ifdef __CYGWIN__
406 /* Cygwin < 1.7 does not have locales. nl_langinfo (CODESET) always
407 returns "US-ASCII". Return the suffix of the locale name from the
408 environment variables (if present) or the codepage as a number. */
409 if (codeset != NULL && strcmp (codeset, "US-ASCII") == 0)
410 {
411 const char *locale;
412 static char buf[2 + 10 + 1];
413
414 locale = getenv ("LC_ALL");
415 if (locale == NULL || locale[0] == '\0')
416 {
417 locale = getenv ("LC_CTYPE");
418 if (locale == NULL || locale[0] == '\0')
419 locale = getenv ("LANG");
420 }
421 if (locale != NULL && locale[0] != '\0')
422 {
423 /* If the locale name contains an encoding after the dot, return
424 it. */
425 const char *dot = strchr (locale, '.');
426
427 if (dot != NULL)
428 {
429 const char *modifier;
430
431 dot++;
432 /* Look for the possible @... trailer and remove it, if any. */
433 modifier = strchr (dot, '@');
434 if (modifier == NULL)
435 return dot;
436 if (modifier - dot < sizeof (buf))
437 {
438 memcpy (buf, dot, modifier - dot);
439 buf [modifier - dot] = '\0';
440 return buf;
441 }
442 }
443 }
444
445 /* The Windows API has a function returning the locale's codepage as a
446 number: GetACP(). This encoding is used by Cygwin, unless the user
447 has set the environment variable CYGWIN=codepage:oem (which very few
448 people do).
449 Output directed to console windows needs to be converted (to
450 GetOEMCP() if the console is using a raster font, or to
451 GetConsoleOutputCP() if it is using a TrueType font). Cygwin does
452 this conversion transparently (see winsup/cygwin/fhandler_console.cc),
453 converting to GetConsoleOutputCP(). This leads to correct results,
454 except when SetConsoleOutputCP has been called and a raster font is
455 in use. */
456 sprintf (buf, "CP%u", GetACP ());
457 codeset = buf;
458 }
459 # endif
460
461 # else
462
463 /* On old systems which lack it, use setlocale or getenv. */
464 const char *locale = NULL;
465
466 /* But most old systems don't have a complete set of locales. Some
467 (like SunOS 4 or DJGPP) have only the C locale. Therefore we don't
468 use setlocale here; it would return "C" when it doesn't support the
469 locale name the user has set. */
470 # if 0
471 locale = setlocale (LC_CTYPE, NULL);
472 # endif
473 if (locale == NULL || locale[0] == '\0')
474 {
475 locale = getenv ("LC_ALL");
476 if (locale == NULL || locale[0] == '\0')
477 {
478 locale = getenv ("LC_CTYPE");
479 if (locale == NULL || locale[0] == '\0')
480 locale = getenv ("LANG");
481 }
482 }
483
484 /* On some old systems, one used to set locale = "iso8859_1". On others,
485 you set it to "language_COUNTRY.charset". In any case, we resolve it
486 through the charset.alias file. */
487 codeset = locale;
488
489 # endif
490
491 #elif defined WINDOWS_NATIVE
492
493 static char buf[2 + 10 + 1];
494
495 /* The Windows API has a function returning the locale's codepage as
496 a number, but the value doesn't change according to what the
497 'setlocale' call specified. So we use it as a last resort, in
498 case the string returned by 'setlocale' doesn't specify the
499 codepage. */
500 char *current_locale = setlocale (LC_ALL, NULL);
501 char *pdot;
502
503 /* If they set different locales for different categories,
504 'setlocale' will return a semi-colon separated list of locale
505 values. To make sure we use the correct one, we choose LC_CTYPE. */
506 if (strchr (current_locale, ';'))
507 current_locale = setlocale (LC_CTYPE, NULL);
508
509 pdot = strrchr (current_locale, '.');
510 if (pdot && 2 + strlen (pdot + 1) + 1 <= sizeof (buf))
511 sprintf (buf, "CP%s", pdot + 1);
512 else
513 {
514 /* The Windows API has a function returning the locale's codepage as a
515 number: GetACP().
516 When the output goes to a console window, it needs to be provided in
517 GetOEMCP() encoding if the console is using a raster font, or in
518 GetConsoleOutputCP() encoding if it is using a TrueType font.
519 But in GUI programs and for output sent to files and pipes, GetACP()
520 encoding is the best bet. */
521 sprintf (buf, "CP%u", GetACP ());
522 }
523 codeset = buf;
524
525 #elif defined OS2
526
527 const char *locale;
528 static char buf[2 + 10 + 1];
529 ULONG cp[3];
530 ULONG cplen;
531
532 codeset = NULL;
533
534 /* Allow user to override the codeset, as set in the operating system,
535 with standard language environment variables. */
536 locale = getenv ("LC_ALL");
537 if (locale == NULL || locale[0] == '\0')
538 {
539 locale = getenv ("LC_CTYPE");
540 if (locale == NULL || locale[0] == '\0')
541 locale = getenv ("LANG");
542 }
543 if (locale != NULL && locale[0] != '\0')
544 {
545 /* If the locale name contains an encoding after the dot, return it. */
546 const char *dot = strchr (locale, '.');
547
548 if (dot != NULL)
549 {
550 const char *modifier;
551
552 dot++;
553 /* Look for the possible @... trailer and remove it, if any. */
554 modifier = strchr (dot, '@');
555 if (modifier == NULL)
556 return dot;
557 if (modifier - dot < sizeof (buf))
558 {
559 memcpy (buf, dot, modifier - dot);
560 buf [modifier - dot] = '\0';
561 return buf;
562 }
563 }
564
565 /* For the POSIX locale, don't use the system's codepage. */
566 if (strcmp (locale, "C") == 0 || strcmp (locale, "POSIX") == 0)
567 codeset = "";
568 }
569
570 if (codeset == NULL)
571 {
572 /* OS/2 has a function returning the locale's codepage as a number. */
573 if (DosQueryCp (sizeof (cp), cp, &cplen))
574 codeset = "";
575 else
576 {
577 sprintf (buf, "CP%u", cp[0]);
578 codeset = buf;
579 }
580 }
581
582 #endif
583
584 if (codeset == NULL)
585 /* The canonical name cannot be determined. */
586 codeset = "";
587
588 /* Resolve alias. */
589 for (aliases = get_charset_aliases ();
590 *aliases != '\0';
591 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
592 if (strcmp (codeset, aliases) == 0
593 || (aliases[0] == '*' && aliases[1] == '\0'))
594 {
595 codeset = aliases + strlen (aliases) + 1;
596 break;
597 }
598
599 /* Don't return an empty string. GNU libc and GNU libiconv interpret
600 the empty string as denoting "the locale's character encoding",
601 thus GNU libiconv would call this function a second time. */
602 if (codeset[0] == '\0')
603 codeset = "ASCII";
604
605 #ifdef DARWIN7
606 /* Mac OS X sets MB_CUR_MAX to 1 when LC_ALL=C, and "UTF-8"
607 (the default codeset) does not work when MB_CUR_MAX is 1. */
608 if (strcmp (codeset, "UTF-8") == 0 && MB_CUR_MAX_L (uselocale (NULL)) <= 1)
609 codeset = "ASCII";
610 #endif
611
612 return codeset;
613 }
614
615 /* A variant of the above, without calls to `setlocale', `nl_langinfo',
616 etc. */
617 const char *
environ_locale_charset(void)618 environ_locale_charset (void)
619 {
620 static char buf[2 + 10 + 1];
621 const char *codeset, *aliases;
622 const char *locale = NULL;
623
624 locale = getenv ("LC_ALL");
625 if (locale == NULL || locale[0] == '\0')
626 {
627 locale = getenv ("LC_CTYPE");
628 if (locale == NULL || locale[0] == '\0')
629 locale = getenv ("LANG");
630 }
631
632 if (locale != NULL && locale[0] != '\0')
633 {
634 /* If the locale name contains an encoding after the dot, return it. */
635 const char *dot = strchr (locale, '.');
636
637 if (dot != NULL)
638 {
639 const char *modifier;
640
641 dot++;
642 /* Look for the possible @... trailer and remove it, if any. */
643 modifier = strchr (dot, '@');
644 if (modifier == NULL)
645 return dot;
646 if (modifier - dot < sizeof (buf))
647 {
648 memcpy (buf, dot, modifier - dot);
649 buf [modifier - dot] = '\0';
650 return buf;
651 }
652 }
653 else if (strcmp (locale, "C") == 0)
654 {
655 strcpy (buf, "ASCII");
656 return buf;
657 }
658 else
659 codeset = "";
660 }
661 else
662 codeset = "";
663
664 /* Resolve alias. */
665 for (aliases = get_charset_aliases ();
666 *aliases != '\0';
667 aliases += strlen (aliases) + 1, aliases += strlen (aliases) + 1)
668 if (strcmp (codeset, aliases) == 0
669 || (aliases[0] == '*' && aliases[1] == '\0'))
670 {
671 codeset = aliases + strlen (aliases) + 1;
672 break;
673 }
674
675 /* Don't return an empty string. GNU libc and GNU libiconv interpret
676 the empty string as denoting "the locale's character encoding",
677 thus GNU libiconv would call this function a second time. */
678 if (codeset[0] == '\0')
679 /* Default to Latin-1, for backward compatibility with Guile 1.8. */
680 codeset = "ISO-8859-1";
681
682 return codeset;
683 }
684