is_in_main_process

FunctionPrivateSource

flag: bool = is_in_main_process()

A function used for checking whether the current process is the main process or not.

The checking is implemented by

https://docs.python.org/3/library/multiprocessing.html#multiprocessing.parent_process

Arguments

Returns

Argument	Type	Description
flag	bool	If True, the current process is the main process. Note that this method is not capable of detecting the process created by the subprocess module.

Examples

Test the performance of multiprocessing

Codes

import multiprocessing as mproc
import subprocess
from dash_file_cache.utilities import is_in_main_process


def test_proc():
    print("multiprocessing:", is_in_main_process())


print("main:", is_in_main_process())
proc = mproc.Process(target=test_proc)
proc.start()
proc.join()
proc.kill()
print(
    "subprocess:",
    subprocess.check_output(
        [
            "python",
            "-c",
            (
                "from dash_file_cache.utilities import is_in_main_process;"
                "print(is_in_main_process())"
            ),
        ],
        text=True,
    ),
)

Results

main: True
multiprocessing: False
subprocess: True