Flags for Word Expansion
------------------------
This section describes the flags that you can specify in the FLAGS
argument to `wordexp'. Choose the flags you want, and combine them
with the C operator `|'.
`WRDE_APPEND'
Append the words from this expansion to the vector of words
produced by previous calls to `wordexp'. This way you can
effectively expand several words as if they were concatenated with
spaces between them.
In order for appending to work, you must not modify the contents
of the word vector structure between calls to `wordexp'. And, if
you set `WRDE_DOOFFS' in the first call to `wordexp', you must also
set it when you append to the results.
`WRDE_DOOFFS'
Leave blank slots at the beginning of the vector of words. The
`we_offs' field says how many slots to leave. The blank slots
contain null pointers.
`WRDE_NOCMD'
Don't do command substitution; if the input requests command
substitution, report an error.
`WRDE_REUSE'
Reuse a word vector made by a previous call to `wordexp'. Instead
of allocating a new vector of words, this call to `wordexp' will
use the vector that already exists (making it larger if necessary).
Note that the vector may move, so it is not safe to save an old
pointer and use it again after calling `wordexp'. You must fetch
`we_pathv' anew after each call.
`WRDE_SHOWERR'
Do show any error messages printed by commands run by command
substitution. More precisely, allow these commands to inherit the
standard error output stream of the current process. By default,
`wordexp' gives these commands a standard error stream that
discards all output.
`WRDE_UNDEF'
If the input refers to a shell variable that is not defined,
report an error.