why ctest can run e.g. arm64 unit test executable file in x64 environment.

[love1angel]

my host is x86 environment, and my compiler is arm64 g++.
I want to debug gtest ut exec file. and i can use ctest in build dir to run unit test. but it failed to use aarch64-poky-linux-gdb run.

This GDB was configured as "--host=x86_64-pokysdk-linux --target=aarch64-poky-linux".
$ uname -a
Linux ubuntu-virtual-machine 5.15.0-56-generic #62~20.04.1-Ubuntu SMP Tue Nov 22 21:24:20 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
$ file ut_settings 
ut_settings: ELF 64-bit LSB shared object, ARM aarch64, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux-aarch64.so.1, BuildID[sha1]=cb6d795bd316fb829ddd26caf317240532105469, for GNU/Linux 3.14.0, with debug_info, not stripped

I used this cmd to run

$ aarch64-poky-linux-gdb --args ./unittests/ut_settings --gtest_filter=SettingsTestSuite.testParseStatus

when i typed run, it cannot run

(gdb) r
Don't know how to run.  Try "help target".

but use ctest it can run. my confussion is why i can use ctest run it, but cannot use gdb in arm64 to run.
I don't know how to. can some one help me how to use gdb run with this ut?
I know can use gdb server run it, but can directly use gdb run it in my host?

$ ctest
Test project /home/helianthus/project/build
        Start   1: KeyHandingTests.testSymmeticKey
  1/191 Test   #1: KeyHandingTests.testSymmeticKey ....................................................   Passed    0.34 sec
        Start   2: KeyHandingTests.testAesCrypto
  2/191 Test   #2: KeyHandingTests.testAesCrypto ......................................................   Passed    0.32 sec

---

the entire log

$ aarch64-poky-linux-gdb --args ./unittests/ut_settings --gtest_filter=SettingsTestSuite.testParseStatus
GNU gdb (GDB) 9.1
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "--host=x86_64-pokysdk-linux --target=aarch64-poky-linux".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from ./unittests/ut_settings...
(gdb) r
Don't know how to run.  Try "help target".
(gdb) help target
Connect to a target machine or process.
The first argument is the type or protocol of the target machine.
Remaining arguments are interpreted by the target protocol.  For more
information on the arguments for a particular protocol, type
`help target ' followed by the protocol name.

List of target subcommands:

target core -- Use a core file as a target.
target exec -- Use an executable file as a target.
target extended-remote -- Use a remote computer via a serial line, using a gdb-specific protocol.
target record-btrace -- Collect control-flow trace and provide the execution history.
target record-core -- Log program while executing and replay execution from log.
target record-full -- Log program while executing and replay execution from log.
target remote -- Use a remote computer via a serial line, using a gdb-specific protocol.
target tfile -- Use a trace file as a target.

Type "help target" followed by target subcommand name for full documentation.
Type "apropos word" to search for commands related to "word".
Type "apropos -v word" for full documentation of commands related to "word".
Command name abbreviations are allowed if unambiguous.

[love1angel]

I use qemu and gdb stub can solve this
start server

qemu-aarch64 -g 1234 ut_settings

connect gdb

aarch64-poky-linux-gdb ut_settings
target remote localhost:1234

but why ctest can run different arch file directly?

[love1angel]

ctest is cmake's tools. sry