The Portals4 testing row looks like a real issue to me, seemingly with the pshmem symbols.
The UCX rows look like a known issue #1148

This looks great, thanks @avincigu!

I noticed an issue with "in-place" scan (the specification example uses the same source and dest buffer). Do you have any other testing in place?

The C11 variants can probably added as well - something like this:

diff --git a/mpp/shmemx.h4 b/mpp/shmemx.h4
index 92b38519..f82729e0 100644
--- a/mpp/shmemx.h4
+++ b/mpp/shmemx.h4
@@ -119,6 +119,19 @@ SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_IBGET', `, \') \
         uint64_t*: shmemx_signal_add \
     )(__VA_ARGS__)

+define(`SHMEM_C11_GEN_EXSCAN', `        $2*: shmemx_$1_sum_exscan')dnl
+#define shmemx_sum_exscan(...) \
+    _Generic(SHMEM_C11_TYPE_EVAL_PTR(SHMEM_C11_ARG1(__VA_ARGS__)), \
+SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_EXSCAN', `, \') \
+    )(__VA_ARGS__)
+
+define(`SHMEM_C11_GEN_INSCAN', `        $2*: shmemx_$1_sum_inscan')dnl
+#define shmemx_sum_inscan(...) \
+    _Generic(SHMEM_C11_TYPE_EVAL_PTR(SHMEM_C11_ARG1(__VA_ARGS__)), \
+SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_INSCAN', `, \') \
+    )(__VA_ARGS__)

The code style is a bit different from typical SOS, at least in collectives.c. We gravitate towards the Google style guide: https://google.github.io/styleguide/cppguide.html

Let's chat offline tomorrow, thanks!

Looking at the PR, I realize why @davidozog commented on code style. I did not see any issue when we were looking at the code @avincigu. Perhaps, it is the editor you were using.

This looks great, thanks @avincigu!

I noticed an issue with "in-place" scan (the specification example uses the same source and dest buffer). Do you have any other testing in place?

The C11 variants can probably added as well - something like this:

diff --git a/mpp/shmemx.h4 b/mpp/shmemx.h4
index 92b38519..f82729e0 100644
--- a/mpp/shmemx.h4
+++ b/mpp/shmemx.h4
@@ -119,6 +119,19 @@ SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_IBGET', `, \') \
         uint64_t*: shmemx_signal_add \
     )(__VA_ARGS__)

+define(`SHMEM_C11_GEN_EXSCAN', `        $2*: shmemx_$1_sum_exscan')dnl
+#define shmemx_sum_exscan(...) \
+    _Generic(SHMEM_C11_TYPE_EVAL_PTR(SHMEM_C11_ARG1(__VA_ARGS__)), \
+SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_EXSCAN', `, \') \
+    )(__VA_ARGS__)
+
+define(`SHMEM_C11_GEN_INSCAN', `        $2*: shmemx_$1_sum_inscan')dnl
+#define shmemx_sum_inscan(...) \
+    _Generic(SHMEM_C11_TYPE_EVAL_PTR(SHMEM_C11_ARG1(__VA_ARGS__)), \
+SHMEM_BIND_C11_RMA(`SHMEM_C11_GEN_INSCAN', `, \') \
+    )(__VA_ARGS__)

The code style is a bit different from typical SOS, at least in collectives.c. We gravitate towards the Google style guide: https://google.github.io/styleguide/cppguide.html

Let's chat offline tomorrow, thanks!

Thanks for the comments Dave! I made the changes you suggested. It seems like my editor was adding extra spaces whenever I hit tab. I have fixed it now, please let me know if you see any style issues still.