a string
a string to compare with @s1
the maximum number of characters to compare
0 if the strings match, a negative value if @s1 < @s2, or a positive value if @s1 > @s2.
Deprecated: The problem with g_strncasecmp() is that it does the comparison by calling toupper()/tolower(). These functions are locale-specific and operate on single bytes. However, it is impossible to handle things correctly from an internationalization standpoint by operating on bytes, since characters may be multibyte. Thus g_strncasecmp() is broken if your string is guaranteed to be ASCII, since it is locale-sensitive, and it's broken if your string is localized, since it doesn't work on many encodings at all, including UTF-8, EUC-JP, etc.
There are therefore two replacement techniques: g_ascii_strncasecmp(), which only works on ASCII and is not locale-sensitive, and g_utf8_casefold() followed by strcmp() on the resulting strings, which is good for case-insensitive sorting of UTF-8.
A case-insensitive string comparison, corresponding to the standard strncasecmp() function on platforms which support it. It is similar to g_strcasecmp() except it only compares the first @n characters of the strings.