On x86, they are both macros for non-standard agreements call
On ARM they do nothing.
The calling Convention is...
• at the level of registers, we called the function;
• who cleans the stack for the caller;
• who is responsible for restoring registers, if they have changed (or there is a risk that they have changed).
stdcall — calling through the stack, right to left, for cleaning up the stack is handled by a function result in eax (rax), the function responsible for restoring the segment registers, esp and ebp, the program for the rest.
On ARM using the Convention cdecl. The same thing, but for cleaning up the stack is responsible for the programme (what is there to ARM registers, I don't know).