dlsym: improve diagnostic.

* sysif.c (dlsym_error): Show the library object and symbol
even when the system has a diagnotic. On Cygwin/Cygnal there
is a generic "No such process" error that doesn't mention the
library or symbol.

1 files changed, 2 insertions, 1 deletions

diff --git a/sysif.c b/sysif.c
index 288f37b4..3e482897 100644
--- a/sysif.c
+++ b/sysif.c
@@ -2228,7 +2228,8 @@ static void dlsym_error(val dlptr, val name, val self)
 {
   char *err = dlerror();
   if (err)
-    uw_throwf(error_s, lit("~a: ~a"), self, string_utf8(err), nao);
+    uw_throwf(error_s, lit("~a: while looking up ~a in ~s: ~a"),
+              self, name, dlptr, string_utf8(err), nao);
   else
     uw_throwf(error_s, lit("~a: ~a not found in ~s"),
               self, name, dlptr, nao);