void exarg_add_usage_header ( char *  header)

Adds user defined header to automatic usage command generated.

Once a program is linked to libexarg is able to produce a usage help by accepting the –usage command line option. But that usage help is showed as is. This function allows you to define a header to be showed preceding the usage info. You can use this, for example, to introduce your copyright.

This function doesn't make a copy of the given string so you must not free the header provided or use an static string.