[Program Options] Bug: empty arguments treated as positional ones

[k-r.ernst@…]

Tested with boost::program_options in 1.39

When an program argument is empty, or contains only whitespace, it it treated as positional argument, confusing program_options

How to reproduce:

1. Get example app which expects 1 positional argument

2. launch it with e.g. execlp("testapp", "testapp", "", "real_positional_argument", NULL);

Observed behavior: Error: "too many positional options"

Expected behavior: Empty argument should be ignored

Additional note: instead of empty string "", the same error happens with only whitespace like " "

[Vladimir Prus]

Could you provide a rationale for ignoring tokens that are either empty strings or whitespace-only? Why are such tokens are passed to the program in the first place? What other programs ignore such tokens?

[Vladimir Prus]

Since you did not provide any rationale, I am closing this bug. Of course, should you wish to follow up, please reopen it.