Abseil flags do not output help info when the executable name is not same as the source file name.

[binbowang1987]

when I use main.cpp as the source file, and test_flag as the executable name. run test_flag --help, the output is

test_flag: Warning: SetProgramUsageMessage() never called

No flags matched.

Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.

I changed main.cpp to test_flag.cpp, the output of test_flag --help is ok.

test_flag: Warning: SetProgramUsageMessage() never called

Flags from test_flag.cpp:
    --image_height (the image height); default: 444;
    --image_width (the image width); default: 444;
    --port (Server port for the service); default: 55555;

Try --helpfull to get a list of all flags or --help=substring shows help for
flags which include specified substring in either in the name, or description or
path.

[derekmauro]

You should be able to set some options using absl::SetFlagsUsageConfig() that will let the library understand which flags are part of --help.