[libdbi-devel] [PATCH] Zero-byte allocations in _dbd_result_set_numfields

[Sami T. <sa...@to...>]

I received a number of warnings about zero-byte allocations when running
an application that uses libdbi under valgrind.

It seems that the memory allocated in _dbd_result_set_numfields is never
freed in dbi_result_free if result->numfields is zero. Yet, calloc seems
to allocate some resources even if the first argument is zero, therefore
leading to a slow memory leak.

Below is a suggested patch to fix _dbd_result_set_numfields.

	Sami


--- dbd_helper.c.orig	2005-12-07 18:01:26.000000000 +0200
+++ dbd_helper.c	2005-12-07 17:45:43.000000000 +0200
@@ -85,9 +85,11 @@
 
 void _dbd_result_set_numfields(dbi_result_t *result, unsigned int numfields) {
 	result->numfields = numfields;
-	result->field_names = calloc(numfields, sizeof(char *));
-	result->field_types = calloc(numfields, sizeof(unsigned short));
-	result->field_attribs = calloc(numfields, sizeof(unsigned int *));
+	if (numfields > 0) {
+		result->field_names = calloc(numfields, sizeof(char *));
+		result->field_types = calloc(numfields, sizeof(unsigned short));
+		result->field_attribs = calloc(numfields, sizeof(unsigned int *));
+	}
 }
 
 void _dbd_result_add_field(dbi_result_t *result, unsigned int idx, char *name, unsigned short type, unsigned int attribs) {