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Diffstat (limited to 'doc/README.dev')
| -rw-r--r-- | doc/README.dev | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/doc/README.dev b/doc/README.dev index d833c477d..caa8255ac 100644 --- a/doc/README.dev +++ b/doc/README.dev @@ -872,10 +872,16 @@ Conversely, do not use locale-dependent functions when the result must not depend on the locales. In particular, the alphanumeric characters used in number strings (as created by mpfr_get_str) must be those of the required characters from the basic character set (see ISO C99 -standard Section 5.2.1 "Character sets"). And tolower(letter) does -not necessarily return the corresponding lowercase letter from these -required characters. For instance, tolower('I') returns a dotless 'i' -in Turkish tr_TR.iso88599 locales. +standard Section 5.2.1 "Character sets"). + +Note that in Turkish locales on some systems: + * the uppercase version of "i" is "İ" (an "I" with a dot above); + * the lowercase version of "I" is "ı" (a dotless "i"). +These characters are available in ISO-8859-9, thus as "char" in the +tr_TR.iso88599 locale. However, in UTF-8, they are not available as +(8-bit) "char"; thus toupper('i') gives 'i' and tolower('I') gives 'I'. +So, when writing code and testing, these two encodings need to be +considered, as they can give different behaviors. =========================================================================== |