usym

Prints the symbol for a specified address. An alias for ufunc.

_usymaddr usym(uintptr_t)

The usym function prints the symbol for a specified address, which is analogous to how uaddr works, but without the hexadecimal offsets. The usym function is an alias for ufunc.

Example 7-64 How to use usym to obtain the symbol for an address

The example shows how to use the usym function to return the symbols for each openat system call when running the date command. The clause is predicated with a check that the process ID matches the target process. The built-in ucaller variable is used to obtain a pointer to the location of the thread at the time the probe is fired.

sudo dtrace -n syscall::openat:entry'/pid == $target/{usym(ucaller);}' -c 'date'

Generates output similar to the following:

CPU     ID                    FUNCTION:NAME
  2 147861                     openat:entry   libc.so.6`_nl_find_locale                         
Mon 20 Feb 18:12:58 GMT 2023
  2 147861                     openat:entry   0x0