diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/cuda/hooks/yaksuri_cuda_init_hooks.c b/src/mpi/datatype/typerep/yaksa/src/backend/cuda/hooks/yaksuri_cuda_init_hooks.c
index 1fe592da9f4..f3984acee1e 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/cuda/hooks/yaksuri_cuda_init_hooks.c
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/cuda/hooks/yaksuri_cuda_init_hooks.c
@@ -73,9 +73,9 @@ static int finalize_hook(void)
     int rc = YAKSA_SUCCESS;
     cudaError_t cerr;
 
-    for (int i = 0; i < yaksuri_cudai_global.ndevices; i++) {
+    for (unsigned i = 0; i < yaksuri_cudai_global.ndevices; i++) {
         if (yaksuri_cudai_global.streams[i].created) {
-            cerr = cudaSetDevice(i);
+            cerr = cudaSetDevice((int) i);
             YAKSURI_CUDAI_CUDA_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
             cerr = cudaStreamDestroy(yaksuri_cudai_global.streams[i].stream);
@@ -93,7 +93,7 @@ static int finalize_hook(void)
     goto fn_exit;
 }
 
-static int get_num_devices(int *ndevices)
+static int get_num_devices(unsigned *ndevices)
 {
     *ndevices = yaksuri_cudai_global.ndevices;
 
@@ -169,21 +169,24 @@ int yaksuri_cuda_init_hook(yaksur_gpudriver_hooks_s ** hooks)
     int rc = YAKSA_SUCCESS;
     cudaError_t cerr;
 
-    cerr = cudaGetDeviceCount(&yaksuri_cudai_global.ndevices);
+    int ndevices;
+    cerr = cudaGetDeviceCount(&ndevices);
     if (cerr == cudaErrorNoDevice || cerr == cudaErrorInsufficientDriver) {
         /* both codes can indicate no devices available on the system */
         goto fn_exit;
     }
     YAKSURI_CUDAI_CUDA_ERR_CHKANDJUMP(cerr, rc, fn_fail);
+    YAKSU_ERR_CHKANDJUMP(ndevices < 0, rc, YAKSA_ERR__INTERNAL, fn_fail);
+    yaksuri_cudai_global.ndevices = (unsigned) ndevices;
 
     if (getenv("CUDA_VISIBLE_DEVICES") == NULL) {
         /* user did not do any filtering for us; if any of the devices
          * is in exclusive mode, disable GPU support to avoid
          * incorrect device sharing */
         bool excl = false;
-        for (int i = 0; i < yaksuri_cudai_global.ndevices; i++) {
+        for (unsigned i = 0; i < yaksuri_cudai_global.ndevices; i++) {
             int mode;
-            cerr = cudaDeviceGetAttribute(&mode, cudaDevAttrComputeMode, i);
+            cerr = cudaDeviceGetAttribute(&mode, cudaDevAttrComputeMode, (int) i);
             YAKSURI_CUDAI_CUDA_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
             if (mode != cudaComputeModeDefault) {
@@ -207,20 +210,20 @@ int yaksuri_cuda_init_hook(yaksur_gpudriver_hooks_s ** hooks)
     yaksuri_cudai_global.streams = calloc(yaksuri_cudai_global.ndevices, sizeof(cudai_stream));
 
     yaksuri_cudai_global.p2p = (int **) malloc(yaksuri_cudai_global.ndevices * sizeof(int *));
-    for (int i = 0; i < yaksuri_cudai_global.ndevices; i++) {
+    for (unsigned i = 0; i < yaksuri_cudai_global.ndevices; i++) {
         if (yaksuri_global.has_wait_kernel) {
             /* The stream creation will deadlock with wait kernel. Create them now. */
-            yaksuri_cudai_get_stream(i);
+            yaksuri_cudai_get_stream((int) i);
         }
         yaksuri_cudai_global.p2p[i] = (int *) malloc(yaksuri_cudai_global.ndevices * sizeof(int));
         /* mark as unchecked with -1. We will check access and cache the value
          * in check_p2p_comm */
-        for (int j = 0; j < yaksuri_cudai_global.ndevices; j++) {
+        for (unsigned j = 0; j < yaksuri_cudai_global.ndevices; j++) {
             yaksuri_cudai_global.p2p[i][j] = -1;
         }
     }
     /* mark self entries */
-    for (int i = 0; i < yaksuri_cudai_global.ndevices; i++) {
+    for (unsigned i = 0; i < yaksuri_cudai_global.ndevices; i++) {
         yaksuri_cudai_global.p2p[i][i] = 1;
     }
 
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/cuda/include/yaksuri_cudai_base.h b/src/mpi/datatype/typerep/yaksa/src/backend/cuda/include/yaksuri_cudai_base.h
index df1504771c4..8bef18c6663 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/cuda/include/yaksuri_cudai_base.h
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/cuda/include/yaksuri_cudai_base.h
@@ -24,7 +24,7 @@ typedef struct cudai_stream_s {
 } cudai_stream;
 
 typedef struct {
-    int ndevices;
+    unsigned ndevices;
     cudai_stream *streams;      /* array of lazily created streams, one for each device */
     int **p2p;                  /* p2p[sdev][ddev] */
 } yaksuri_cudai_global_s;
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/hip/hooks/yaksuri_hip_init_hooks.c b/src/mpi/datatype/typerep/yaksa/src/backend/hip/hooks/yaksuri_hip_init_hooks.c
index b51665f6f83..0e1e6f10ce8 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/hip/hooks/yaksuri_hip_init_hooks.c
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/hip/hooks/yaksuri_hip_init_hooks.c
@@ -64,8 +64,8 @@ static int finalize_hook(void)
     int rc = YAKSA_SUCCESS;
     hipError_t cerr;
 
-    for (int i = 0; i < yaksuri_hipi_global.ndevices; i++) {
-        cerr = hipSetDevice(i);
+    for (unsigned i = 0; i < yaksuri_hipi_global.ndevices; i++) {
+        cerr = hipSetDevice((int) i);
         YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
         cerr = hipStreamDestroy(yaksuri_hipi_global.stream[i]);
@@ -82,7 +82,7 @@ static int finalize_hook(void)
     goto fn_exit;
 }
 
-static int get_num_devices(int *ndevices)
+static int get_num_devices(unsigned *ndevices)
 {
     *ndevices = yaksuri_hipi_global.ndevices;
 
@@ -107,21 +107,24 @@ int yaksuri_hip_init_hook(yaksur_gpudriver_hooks_s ** hooks)
     int rc = YAKSA_SUCCESS;
     hipError_t cerr;
 
-    cerr = hipGetDeviceCount(&yaksuri_hipi_global.ndevices);
+    int ndevices;
+    cerr = hipGetDeviceCount(&ndevices);
     if (cerr == hipErrorNoDevice) {
         goto fn_exit;
     }
     YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
+    YAKSU_ERR_CHKANDJUMP(ndevices < 0, rc, YAKSA_ERR__INTERNAL, fn_fail);
+    yaksuri_hipi_global.ndevices = (unsigned) ndevices;
 
     if (getenv("HIP_VISIBLE_DEVICES") == NULL) {
         /* user did not do any filtering for us; if any of the devices
          * is in exclusive mode, disable GPU support to avoid
          * incorrect device sharing */
         bool excl = false;
-        for (int i = 0; i < yaksuri_hipi_global.ndevices; i++) {
+        for (unsigned i = 0; i < yaksuri_hipi_global.ndevices; i++) {
             struct hipDeviceProp_t prop;
 
-            cerr = hipGetDeviceProperties(&prop, i);
+            cerr = hipGetDeviceProperties(&prop, (int) i);
             YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
             if (prop.computeMode != hipComputeModeDefault) {
@@ -146,7 +149,7 @@ int yaksuri_hip_init_hook(yaksur_gpudriver_hooks_s ** hooks)
         malloc(yaksuri_hipi_global.ndevices * sizeof(hipStream_t));
 
     yaksuri_hipi_global.p2p = (bool **) malloc(yaksuri_hipi_global.ndevices * sizeof(bool *));
-    for (int i = 0; i < yaksuri_hipi_global.ndevices; i++) {
+    for (unsigned i = 0; i < yaksuri_hipi_global.ndevices; i++) {
         yaksuri_hipi_global.p2p[i] = (bool *) malloc(yaksuri_hipi_global.ndevices * sizeof(bool));
     }
 
@@ -154,23 +157,23 @@ int yaksuri_hip_init_hook(yaksur_gpudriver_hooks_s ** hooks)
     cerr = hipGetDevice(&cur_device);
     YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
-    for (int i = 0; i < yaksuri_hipi_global.ndevices; i++) {
-        cerr = hipSetDevice(i);
+    for (unsigned i = 0; i < yaksuri_hipi_global.ndevices; i++) {
+        cerr = hipSetDevice((int) i);
         YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
         cerr = hipStreamCreateWithFlags(&yaksuri_hipi_global.stream[i], hipStreamNonBlocking);
         YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
-        for (int j = 0; j < yaksuri_hipi_global.ndevices; j++) {
+        for (unsigned j = 0; j < yaksuri_hipi_global.ndevices; j++) {
             if (i == j) {
                 yaksuri_hipi_global.p2p[i][j] = 1;
             } else {
                 int val;
-                cerr = hipDeviceCanAccessPeer(&val, i, j);
+                cerr = hipDeviceCanAccessPeer(&val, (int) i, (int) j);
                 YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
 
                 if (val) {
-                    cerr = hipDeviceEnablePeerAccess(j, 0);
+                    cerr = hipDeviceEnablePeerAccess((int) j, 0);
                     if (cerr != hipErrorPeerAccessAlreadyEnabled) {
                         YAKSURI_HIPI_HIP_ERR_CHKANDJUMP(cerr, rc, fn_fail);
                     }
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/hip/include/yaksuri_hipi_base.h b/src/mpi/datatype/typerep/yaksa/src/backend/hip/include/yaksuri_hipi_base.h
index 6d4b6e4c401..18cf38bd331 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/hip/include/yaksuri_hipi_base.h
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/hip/include/yaksuri_hipi_base.h
@@ -19,7 +19,7 @@
     } while (0)
 
 typedef struct {
-    int ndevices;
+    unsigned ndevices;
     hipStream_t *stream;
     bool **p2p;
 } yaksuri_hipi_global_s;
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_hooks.c b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_hooks.c
index e89b1e0ce8d..99dc66af6c7 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_hooks.c
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_hooks.c
@@ -22,7 +22,7 @@ static void *malloc_fn(uintptr_t size, void *state)
 
         if (state == &yaksuri_global.gpudriver[id].host) {
             return yaksuri_global.gpudriver[id].hooks->host_malloc(size);
-        } else {
+        } else if (yaksuri_global.gpudriver[id].ndevices > 0) {
             uintptr_t start = (uintptr_t) yaksuri_global.gpudriver[id].device;
             uintptr_t end =
                 (uintptr_t) & yaksuri_global.gpudriver[id].device[yaksuri_global.
@@ -49,7 +49,7 @@ static void free_fn(void *buf, void *state)
         if (state == &yaksuri_global.gpudriver[id].host) {
             yaksuri_global.gpudriver[id].hooks->host_free(buf);
             return;
-        } else {
+        } else if (yaksuri_global.gpudriver[id].ndevices > 0) {
             uintptr_t start = (uintptr_t) yaksuri_global.gpudriver[id].device;
             uintptr_t end =
                 (uintptr_t) & yaksuri_global.gpudriver[id].device[yaksuri_global.
@@ -109,13 +109,13 @@ int yaksur_init_hook(yaksi_info_s * info)
                                      &yaksuri_global.gpudriver[id].host);
         YAKSU_ERR_CHECK(rc, fn_fail);
 
-        int ndevices;
+        unsigned ndevices;
         rc = yaksuri_global.gpudriver[id].hooks->get_num_devices(&ndevices);
         YAKSU_ERR_CHECK(rc, fn_fail);
 
         yaksuri_global.gpudriver[id].device = (yaksu_buffer_pool_s *)
             malloc(ndevices * sizeof(yaksu_buffer_pool_s));
-        for (int i = 0; i < ndevices; i++) {
+        for (unsigned i = 0; i < ndevices; i++) {
             rc = yaksu_buffer_pool_alloc(YAKSURI_TMPBUF_EL_SIZE, 1, YAKSURI_TMPBUF_NUM_EL,
                                          malloc_fn, free_fn,
                                          &yaksuri_global.gpudriver[id].device[i],
@@ -153,8 +153,8 @@ int yaksur_finalize_hook(void)
         rc = yaksu_buffer_pool_free(yaksuri_global.gpudriver[id].host);
         YAKSU_ERR_CHECK(rc, fn_fail);
 
-        int ndevices = yaksuri_global.gpudriver[id].ndevices;
-        for (int i = 0; i < ndevices; i++) {
+        unsigned ndevices = yaksuri_global.gpudriver[id].ndevices;
+        for (unsigned i = 0; i < ndevices; i++) {
             rc = yaksu_buffer_pool_free(yaksuri_global.gpudriver[id].device[i]);
             YAKSU_ERR_CHECK(rc, fn_fail);
         }
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_pre.h b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_pre.h
index e18f0e35d83..e1965dc3edb 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_pre.h
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksur_pre.h
@@ -55,7 +55,7 @@ typedef void (*yaksur_hostfn_t) (void *userData);
 
 typedef struct yaksur_gpudriver_hooks_s {
     /* miscellaneous */
-    int (*get_num_devices) (int *ndevices);
+    int (*get_num_devices) (unsigned *ndevices);
     /* *INDENT-OFF* */
     bool (*check_p2p_comm) (int sdev, int ddev);
     /* *INDENT-ON* */
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksuri.h b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksuri.h
index 42f93eceb97..fe821fff145 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksuri.h
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/src/yaksuri.h
@@ -31,7 +31,7 @@ typedef struct {
         yaksu_buffer_pool_s host;
         yaksu_buffer_pool_s *device;
         yaksur_gpudriver_hooks_s *hooks;
-        int ndevices;
+        unsigned ndevices;
     } gpudriver[YAKSURI_GPUDRIVER_ID__LAST];
 } yaksuri_global_s;
 extern yaksuri_global_s yaksuri_global;
diff --git a/src/mpi/datatype/typerep/yaksa/src/backend/ze/hooks/yaksuri_ze_init_hooks.c b/src/mpi/datatype/typerep/yaksa/src/backend/ze/hooks/yaksuri_ze_init_hooks.c
index b9944abe244..3cb04c2029c 100644
--- a/src/mpi/datatype/typerep/yaksa/src/backend/ze/hooks/yaksuri_ze_init_hooks.c
+++ b/src/mpi/datatype/typerep/yaksa/src/backend/ze/hooks/yaksuri_ze_init_hooks.c
@@ -96,7 +96,7 @@ static int finalize_hook(void)
     goto fn_exit;
 }
 
-static int get_num_devices(int *ndevices)
+static int get_num_devices(unsigned *ndevices)
 {
     *ndevices = yaksuri_zei_global.ndevices;