Re: Some observations building gnuplot for win by gcc-4.9.2 (MinGW64)

[Allin C. <cot...@wf...>]

On Fri, 6 Mar 2015, Tatsuro MATSUOKA wrote:

> I have executed a short test using nmh
> https://github.com/shnya/nmh
>
> Perhaps it is better to use ICU - International Components for Unicode but
> I used nmh for rough test.
>
> Applied changes:
>
> --- gp_cairo.orig.c2014-12-14 08:42:38.000000000 +0900
> +++ gp_cairo.c2015-03-06 10:04:45.142151900 +0900
> @@ -76,6 +76,7 @@
>  
>  #include <pango/pangocairo.h>
>  #include <glib.h>
> +#include <nmh.h>
>  
>  #ifdef _MSC_VER
>  #define rint(x) floor((x)+0.5L)
> @@ -732,14 +733,21 @@
>  gsize bytes_read;
>  GError *error = NULL;
>  const char *charset = NULL;
> +const unsigned char *ucharset = NULL;
>  gchar * string_utf8;
>  
> -if (g_utf8_validate(string, -1, NULL)) {
> -    string_utf8 = g_strdup(string);
> -} else {
> -    charset = gp_cairo_get_encoding(plot);
> -    string_utf8 = g_convert(string, -1, "UTF-8", charset, &bytes_read, NULL, &error);
> -}
> +charset = gp_cairo_get_encoding(plot);
> +ucharset = charset;
> +fprintf(stderr, "%f\n", nmh_is_utf8(ucharset, strlen(ucharset)));
> +       if (nmh_is_utf8(ucharset, strlen(ucharset))) { 
> +fprintf(stderr, "%f\n", nmh_is_utf8(ucharset, strlen(ucharset)));
> +   string_utf8 = g_convert(string, -1, "UTF-8", charset, &bytes_read, NULL, &error); 

Bug right there: according to the documentation for g_convert, it's OK 
to pass NULL in place of the "bytes_read" pointer argument, but _not_
in place of the "bytes_written" (second to last) argument. So it's
to be expected that you get a segfault here.

(BTW, I don't see the point of the nmh test on the "ucharset" string: 
surely that's just the identifier of an encoding and will always be 
ASCII -- and hence also UTF-8.)

Allin Cottrell