email plugin: Fix a format string.

diff --git a/src/email.c b/src/email.c
index 9b82e10..fbdc785 100644 (file)
--- a/src/email.c
+++ b/src/email.c
@@ -292,8 +292,9 @@ static void *collect (void *arg)
 
                        len = strlen (line);
                        if (('\n' != line[len - 1]) && ('\r' != line[len - 1])) {
-                               log_warn ("[thread #%5lu] line too long (> %lu characters): "
-                                               "'%s' (truncated)", self, sizeof (line) - 1, line);
+                               log_warn ("[thread #%5lu] line too long (> %zu characters): "
+                                               "'%s' (truncated)",
+                                               (unsigned long) self, sizeof (line) - 1, line);
 
                                while (NULL != fgets (line, sizeof (line), this->socket))
                                        if (('\n' == line[len - 1]) || ('\r' == line[len - 1]))