Rust Apps for Apache NuttX RTOS: Main Function is Missing. See https://github.com/lupyuen/nuttx-rust-app

missing-main-function.log

$ temu root-riscv64.cfg
TinyEMU Emulator for Ox64 BL808 RISC-V SBC
virtio_console_init
Patched DCACHE.IALL (Invalidate all Page Table Entries in the D-Cache) at 0x5020099a
Patched SYNC.S (Ensure that all Cache Operations are completed) at 0x5020099e
Found ECALL (Start System Timer) at 0x5020bfac
Patched RDTIME (Read System Time) at 0x5020bfb2
elf_len=0
virtio_console_resize_event
ABCnx_start: Entry
uart_register: Registering /dev/console
work_start_lowpri: Starting low-priority kernel worker thread(s)
nxtask_activate: lpwork pid=1,TCB=0x50409110
nxtask_activate: AppBringUp pid=2,TCB=0x50409710
nx_start_application: Starting init task: /system/bin/init
elf_symname: Symbol has no name
elf_symvalue: SHN_UNDEF: Failed to get symbol name: -3
elf_relocateadd: Section 2 reloc 2: Undefined symbol[0] has no name: -3
nxtask_activate: /system/bin/init pid=3,TCB=0x5040b730
nxtask_exit: AppBringUp pid=2,TCB=0x50409710

NuttShell (NSH) NuttX-12.4.0-RC0
nsh> nx_start: CPU0: Beginning Idle Loop

nsh> 
nsh> hello_rust
posix_spawn: pid=0x80202968 path=hello_rust file_actions=0x80202970 attr=0x80202978 argv=0x80202a18
elf_symname: Symbol has no name
elf_symvalue: SHN_UNDEF: Failed to get symbol name: -3
elf_relocateadd: Section 2 reloc 1: Undefined symbol[0] has no name: -3
elf_symvalue: SHN_UNDEF: Exported symbol "main" not found
elf_relocateadd: Section 2 reloc 4: Failed to get value of symbol[7684]: -2
elf_loadbinary: Failed to bind symbols program binary: -2
exec_internal: ERROR: Failed to load program 'hello_rust': -2
nxposix_spawn_exec: ERROR: exec failed: 2
nsh: hello_rust: command not found
nsh>