Tcl_Concat is a utility procedure used by several of the
Tcl commands. Given a collection of strings, it concatenates
them together into a single string, with the original strings
separated by spaces. This procedure behaves differently than
Tcl_Merge, in that the arguments are simply concatenated:
no effort is made to ensure proper list structure.
However, in most common usage the arguments will all be proper
lists themselves; if this is true, then the result will also have
proper list structure.
Tcl_Concat eliminates leading and trailing white space as it
copies strings from argv to the result. If an element of
argv consists of nothing but white space, then that string
is ignored entirely. This white-space removal was added to make
the output of the concat command cleaner-looking.
The result string is dynamically allocated
using Tcl_Alloc; the caller must eventually release the space
by calling Tcl_Free.