diff --git a/mem.c b/mem.c
index 6e5ec44..5f2f0c6 100644
--- a/mem.c
+++ b/mem.c
@@ -294,7 +294,7 @@ static XC_MEM_INIT(xc_mem_init) /* {{{ */
 #define MINSIZE (ALIGN(sizeof(xc_mem_t)) + sizeof(xc_block_t))
 	/* requires at least the header and 1 tail block */
 	if (size < MINSIZE) {
-		fprintf(stderr, "xc_mem_init requires %d bytes at least\n", MINSIZE);
+		fprintf(stderr, "xc_mem_init requires %lu bytes at least\n", (unsigned long) MINSIZE);
 		return NULL;
 	}
 	mem->shm = shm;
diff --git a/xc_malloc.c b/xc_malloc.c
index 88b40bc..863a445 100644
--- a/xc_malloc.c
+++ b/xc_malloc.c
@@ -120,7 +120,7 @@ static XC_MEM_INIT(xc_mem_malloc_init) /* {{{ */
 #define MINSIZE (ALIGN(sizeof(xc_mem_t)))
 	/* requires at least the header and 1 tail block */
 	if (size < MINSIZE) {
-		fprintf(stderr, "xc_mem_malloc_init requires %d bytes at least\n", MINSIZE);
+		fprintf(stderr, "xc_mem_malloc_init requires %lu bytes at least\n", (unsigned long) MINSIZE);
 		return NULL;
 	}
 	mem->shm = shm;
diff --git a/xcache.c b/xcache.c
index 66f9ac9..1197c0b 100644
--- a/xcache.c
+++ b/xcache.c
@@ -1741,7 +1741,7 @@ static int xcache_admin_auth_check(TSRMLS_D) /* {{{ */
 		zend_bailout();
 	}
 	if (strlen(admin_pass) != 32) {
-		php_error_docref(NULL TSRMLS_CC, E_ERROR, "unexpect %d bytes of xcache.admin.pass, expected 32 bytes, the password after md5()", strlen(admin_pass));
+		php_error_docref(NULL TSRMLS_CC, E_ERROR, "unexpect %lu bytes of xcache.admin.pass, expected 32 bytes, the password after md5()", (unsigned long) strlen(admin_pass));
 		zend_bailout();
 	}