[DTrace-devel] [PATCH 2/2] Use a consistent type for dtrace_consume()
Kris Van Hees
kris.van.hees at oracle.com
Fri Aug 15 15:35:14 UTC 2025
On Tue, Aug 12, 2025 at 06:46:06PM -0400, eugene.loh--- via DTrace-devel wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
>
> For a long time, the type of dtrace_consume() has been
> - int according to libdtrace/dtrace.h
> - dtrace_workstatus_t according to libdtrace/dt_consume.c
>
> With some recent compilers, however, this triggers the warning (redacted
> here):
>
> libdtrace/dt_consume.c:3041:1: warning: conflicting types
> for ???dtrace_consume??? due to enum/integer mismatch;
> have ???dtrace_workstatus_t(...)??? [-Wenum-int-mismatch]
> 3041 | dtrace_consume(...)
> | ^~~~~~~~~~~~~~
> In file included from libdtrace/dt_impl.h:14,
> from libdtrace/dt_consume.c:16:
> libdtrace/dtrace.h:210:12: note: previous declaration of
> ???dtrace_consume??? with type ???int(...)???
> 210 | extern int dtrace_consume(...)
> | ^~~~~~~~~~~~~~
>
> which is a nuisance.
>
> Note that dtrace_consume() is called from only one site, where its
> value is compared to DTRACE_WORKSTATUS_ERROR, which is an argument
> for the dtrace_workstatus_t type.
>
> On the other hand, dtrace_consume() is defined to return a variety
> of values, like 0, dt_set_errno(), and dt_consume_cpu(), all of which
> are int, but also DTRACE_WORKSTATUS_OKAY, DTRACE_WORKSTATUS_ERROR,
> and rval, all of which are dtrace_workstatus_t. But then rval itself
> is set to dtrace_workstatus_t dt_consume_begin() or int
> dt_consume_cpu(). So, there is simply no consistency here.
>
> Having the prototype be dtrace_workstatus_t requires some amount
> of code refactoring.
>
> Just change the definition to int and clean up the warning.
>
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>
... I admit this was my fault. I tried to refactor the code so that we could
have dtrace_consume() return dtrace_workstatus_t, but only got this far.
I agree that for now, changing the return type of dtrace_consume() is the
best action to get rid of the compiler warning. Maybe we can revisit the
actual refactoring work later to clean this up properly.
> ---
> libdtrace/dt_consume.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libdtrace/dt_consume.c b/libdtrace/dt_consume.c
> index 07b19d498..d9be563d9 100644
> --- a/libdtrace/dt_consume.c
> +++ b/libdtrace/dt_consume.c
> @@ -3037,7 +3037,7 @@ dt_consume_fini(dtrace_hdl_t *dtp)
> dt_htab_destroy(dtp->dt_spec_bufs);
> }
>
> -dtrace_workstatus_t
> +int
> dtrace_consume(dtrace_hdl_t *dtp, FILE *fp, dtrace_consume_probe_f *pf,
> dtrace_consume_rec_f *rf, void *arg)
> {
> --
> 2.47.3
>
>
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