diff --git a/lib/capn-malloc.c b/lib/capn-malloc.c
index 7a2977c..525ae99 100644
--- a/lib/capn-malloc.c
+++ b/lib/capn-malloc.c
@@ -14,6 +14,11 @@
 #include <limits.h>
 #include <errno.h>
 
+/* Visual Studio notes:
+ * Unless capn_segment is defined with __declspec(align(64)), check_segment_alignment
+ * Fails to compile in x86 mode, as (sizeof(struct capn_segment)&7) -> (44 & 7) evaluates to 4
+ * Compiles in x64 mode, as (sizeof(struct capn_segment)&7) -> (80 & 7) evaluates to 0 
+ */
 struct check_segment_alignment {
 	unsigned int foo : (sizeof(struct capn_segment)&7) ? -1 : 1;
 };
diff --git a/lib/capn.c b/lib/capn.c
index 82df285..60e139c 100644
--- a/lib/capn.c
+++ b/lib/capn.c
@@ -11,7 +11,9 @@
 
 #include <stdlib.h>
 #include <string.h>
+#ifndef _MSC_VER
 #include <sys/param.h>
+#endif
 
 #define STRUCT_PTR 0
 #define LIST_PTR 1
@@ -316,7 +318,7 @@ static char *struct_ptr(struct capn_segment *s, char *d, int minsz) {
 static capn_ptr read_ptr(struct capn_segment *s, char *d) {
 	capn_ptr ret = {CAPN_NULL};
 	uint64_t val;
-	char *e;
+	char *e = 0;
 
 	val = capn_flip64(*(uint64_t*) d);
 
diff --git a/lib/capnp_c.h b/lib/capnp_c.h
index 63cf64d..e96ce01 100644
--- a/lib/capnp_c.h
+++ b/lib/capnp_c.h
@@ -15,6 +15,11 @@
 #include <stdio.h>
 #include <endian.h>
 
+// ssize_t is not defined in stdint.h in MSVC. 
+#ifdef _MSC_VER
+typedef intmax_t ssize_t;
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -96,6 +101,9 @@ struct capn_tree *capn_tree_insert(struct capn_tree *root, struct capn_tree *n);
  * data, len, cap, and user should all set by the user. Other values
  * should be zero initialized.
  */
+#ifdef _MSC_VER
+__declspec(align(64))
+#endif
 struct capn_segment {
 	struct capn_tree hdr;
 	struct capn_segment *next;