diff --git a/src/platform/shm_linux.cpp b/src/platform/shm_linux.cpp
index a019eb9..706a37d 100644
--- a/src/platform/shm_linux.cpp
+++ b/src/platform/shm_linux.cpp
@@ -134,9 +134,8 @@ void release(id_t id) {
     auto ii = static_cast<id_info_t*>(id);
     if (ii->mem_ == nullptr || ii->size_ == 0) {
         ipc::error("fail release: invalid id (mem = %p, size = %zd)\n", ii->mem_, ii->size_);
-        return;
     }
-    if (acc_of(ii->mem_, ii->size_).fetch_sub(1, std::memory_order_acquire) == 1) {
+    else if (acc_of(ii->mem_, ii->size_).fetch_sub(1, std::memory_order_acquire) == 1) {
         ::munmap(ii->mem_, ii->size_);
         ::shm_unlink(ii->name_.c_str());
     }
diff --git a/src/platform/shm_win.cpp b/src/platform/shm_win.cpp
index afb3bb2..3e1408c 100644
--- a/src/platform/shm_win.cpp
+++ b/src/platform/shm_win.cpp
@@ -94,14 +94,12 @@ void release(id_t id) {
     auto ii = static_cast<id_info_t*>(id);
     if (ii->mem_ == nullptr || ii->size_ == 0) {
         ipc::error("fail release: invalid id (mem = %p, size = %zd)\n", ii->mem_, ii->size_);
-        return;
     }
+    else ::UnmapViewOfFile(static_cast<LPCVOID>(ii->mem_));
     if (ii->h_ == NULL) {
         ipc::error("fail release: invalid id (h = null)\n");
-        return;
     }
-    ::UnmapViewOfFile(static_cast<LPCVOID>(ii->mem_));
-    ::CloseHandle(ii->h_);
+    else ::CloseHandle(ii->h_);
     mem::free(ii);
 }
 
diff --git a/src/shm.cpp b/src/shm.cpp
index 71e3a2a..2b3f8c2 100644
--- a/src/shm.cpp
+++ b/src/shm.cpp
@@ -65,12 +65,10 @@ bool handle::acquire(char const * name, std::size_t size, unsigned mode) {
 }
 
 void handle::release() {
-    if (!valid()) return;
     shm::release(detach());
 }
 
 void* handle::get() const {
-    if (!valid()) return nullptr;
     return impl(p_)->m_;
 }
 
@@ -82,7 +80,6 @@ void handle::attach(id_t id) {
 }
 
 id_t handle::detach() {
-    if (!valid()) return nullptr;
     auto old = impl(p_)->id_;
     impl(p_)->id_ = nullptr;
     impl(p_)->m_  = nullptr;