> On 8 Mar 2018, at 11:21, Toke Høiland-Jørgensen <t...@toke.dk> wrote: > >> >> Oh and curiously the bad values go away if you ask for json output >> it’s much better. Which rather points at a ‘feature’ of the >> ‘print_string’ behaviour. > > Right. Well, the print_* functions are behind several levels of > pre-processor indirection, so not quite obvious what's going on here. > Don't really see why they should spit out garbage values, though. > > > Stephen, do you have any ideas? > > -Toke
Right, cracked it and it’s horrible!
print_uint is expanded thus: Note the type of value uint64_t
void print_color_uint(enum output_type t, enum color_attr color,
const char *key, const char *fmt, uint64_t value);
static inline void print_uint (enum output_type t,
const char *key, const char *fmt, uint64_t value)
{ print_color_uint( t, COLOR_NONE,
key, fmt, value); };
So far so good.
print_color_uint expands to:
void print_color_uint(enum output_type t, enum color_attr color,
const char *key, const char *fmt, uint64_t value)
{
if (((t & PRINT_JSON || t & PRINT_ANY) && _jw))
{ if (!key) jsonw_uint(_jw, value);
else jsonw_uint_field(_jw, key, value);
}
else if ((!_jw && (t & PRINT_FP || t & PRINT_ANY)))
{ color_fprintf( (stdout) , color, fmt, value);
}
};
Again, no issue and we eventually call color_fprintf
int color_fprintf(FILE *fp, enum color_attr attr, const char *fmt, ...)
{
int ret = 0;
va_list args;
va_start(args, fmt);
if (!color_is_enabled || attr == COLOR_NONE) {
ret = vfprintf(fp, fmt, args);
goto end;
}
Now, color_printf is a variable argument list function and as such is dependent
upon being told the correct size of argument variables in the fmt variable.
And that’s our problem, we’re passing a 64bit integer but telling the format
string that it’s ‘int’…which I’m guessing can be variable sizes depending on
architecture, as can the endianness.
If we instead do (in q_cake.c)
#include <inttypes.h>
print_uint(PRINT_ANY, "min_transport_size", " min/max transport layer size:
%10" PRIu64, stnc->min_trnlen);
it works. This needs sanity checking by a clever person.
Cheers,
Kevin D-B
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