[DTrace-devel] [PATCH 2/2] Use a consistent type for dtrace_consume()

[eugene.loh at oracle.com]

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>
---
 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