pid return Probes

A return probe fires when the traced function returns or makes a tail call to another function. The value for arg0 is the offset in the function of the return instruction; arg1 holds the return value.

In 32-bit processes, for functions that return either a signed long long or an unsigned long long type, arg1 contains only half of the total bits in the return value. The other half of the total bits returned is available in arg2. On SPARC systems, arg1 contains the upper 32-bits of the return value and arg2 contains the lower 32-bits of the return value. On x86 systems, arg1 contains the lower 32-bits of the return value and arg2 contains the upper 32-bits of the return value.