DPP: Linker issue with functions implemented in C header files

[Andre Pany via Digitalmars-d-learn]

Hi,

I try to get wrap the "Azure SDK for C" using DPP and have 
following issue.
Functions, which are actually implemented in C header files will 
cause
linker errors:
https://github.com/Azure/azure-sdk-for-c/blob/master/sdk/core/core/inc/az_span.h#L91

Example:
AZ_NODISCARD AZ_INLINE az_span az_span_init(uint8_t * ptr, 
int32_t length, int32_t capacity) {
  return (az_span){ ._internal = { .ptr = ptr, .length = length, 
.capacity = capacity, }, };
}

Error message:
/tmp/app.o:az_storage_blobs.d:function 
_D20blobs_client_example__T19AZ_SPAN_FROM_BUFFERTG4096hZQBdFNbQnZS16az_storage_blobs7az_span: error: undefined reference to 'az_span_init'

I do not know C well, is this the expected behavior and should I 
ask the Azure SDK developers to not implement functions within C 
header files?

Kind regards
André