diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 8ab51c4..f3c7ba0 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -39,8 +39,8 @@ jobs:
     - uses: actions/checkout@v2
     - name: configure
       run: |
-          echo running ./configure ${{ matrix.clionly }}
-          ./configure ${{ matrix.clionly }}
+          echo running ./configure ${{ matrix.clionly }} ${{ matrix.debugprintf }} --with-werror
+          ./configure ${{ matrix.clionly }} ${{ matrix.debugprintf }}    --with-werror
     - name: make
       run: nproc && make -j$(nproc)
     - name: check executable
diff --git a/src/large-io.c b/src/large-io.c
index 79228cc..bb737fd 100644
--- a/src/large-io.c
+++ b/src/large-io.c
@@ -46,7 +46,7 @@
 /* The original windows ftruncate has off_size (32bit) */
 
 int large_ftruncate(int fd, gint64 size)
-{  gint32 handle;
+{  intptr_t handle;
 
    if((handle=_get_osfhandle(fd)) == -1)
      return -1;
diff --git a/src/rs03-create.c b/src/rs03-create.c
index 17375de..9fa5797 100644
--- a/src/rs03-create.c
+++ b/src/rs03-create.c
@@ -806,7 +806,7 @@ static gpointer io_thread(ecc_closure *ec)
    /*** Allocate local parity buffer aligned at 128bit boundary */
 
    ec->paritybase = g_malloc(n_parity_bytes+16);      /* output buffer */
-   ec->parity     = ec->paritybase + (16- ((unsigned long)ec->paritybase & 15));
+   ec->parity     = ec->paritybase + (16- ((intptr_t)ec->paritybase & 15));
 
    /*** Create buffer for the ndata input layers 
         Space is provided for one more sector so that
diff --git a/src/scsi-layer.c b/src/scsi-layer.c
index 11cb844..6053e1b 100644
--- a/src/scsi-layer.c
+++ b/src/scsi-layer.c
@@ -48,7 +48,7 @@ AlignedBuffer* CreateAlignedBuffer(int size)
 {  AlignedBuffer *ab = g_malloc0(sizeof(AlignedBuffer));
 
    ab->base = g_malloc(size+4096);
-   ab->buf  = ab->base + (4096 - ((unsigned long)ab->base & 4095));
+   ab->buf  = ab->base + (4096 - ((intptr_t)ab->base & 4095));
 
    return ab;
 }