commandline argument parameter limitation

If you are passing 10,000 arguments to a program, you should be putting those arguments in a file and reading the file from disk.

It depends on the OS:

See Command prompt (Cmd. exe) command-line string limitation on the Microsoft Support site.

On computers running Microsoft Windows XP or later, the maximum length of the string that you can use at the command prompt is 8191 characters. On computers running Microsoft Windows 2000 or Windows NT 4.0, the maximum length of the string that you can use at the command prompt is 2047 characters.

(emphasis mine)

In regards to the size of a string array - if you have many millions of strings in a string array - you are mostly limited by the amount of memory available.