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26 .Dd September 30, 2015
31 .Nd "perform shell-style word expansions"
37 .Fn wordexp "const char * restrict words" "wordexp_t * restrict we" "int flags"
39 .Fn wordfree "wordexp_t *we"
43 function performs shell-style word expansion on
45 and places the list of words into the
49 and the number of words into
54 argument is the bitwise inclusive OR of any of the following constants:
55 .Bl -tag -width ".Dv WRDE_SHOWERR"
57 Append the words to those generated by a previous call to
62 pointers as are specified by the
66 are added to the front of
69 Disallow command substitution in
77 argument was passed to a previous successful call to
79 but has not been passed to
81 The implementation may reuse the space allocated to it.
83 Do not redirect shell error messages to
86 Report error on an attempt to expand an undefined shell variable.
91 structure is defined in
94 .Bd -literal -offset indent
96 size_t we_wordc; /* count of words matched */
97 char **we_wordv; /* pointer to list of words */
98 size_t we_offs; /* slots to reserve in we_wordv */
104 function frees the memory allocated by
106 .Sh IMPLEMENTATION NOTES
109 function is implemented using the undocumented
111 shell built-in command.
115 function returns zero if successful, otherwise it returns one of the following
117 .Bl -tag -width ".Dv WRDE_NOSPACE"
121 argument contains one of the following unquoted characters:
133 An error after successful parsing,
134 such as an attempt to expand an undefined shell variable with
139 An attempt was made to use command substitution and
144 Not enough memory to store the result or
148 Shell syntax error in
154 function returns no value.
156 .Bl -tag -width ".Ev IFS"
161 Invoke the editor on all
163 files in the current directory
166 (error checking omitted):
167 .Bd -literal -offset indent
170 wordexp("${EDITOR:-vi} *.c /etc/motd", &we, 0);
171 execvp(we.we_wordv[0], we.we_wordv);
174 Diagnostic messages from the shell are written to the standard error output
195 implementation does not recognize multibyte characters other than UTF-8, since
196 the shell (which it invokes to perform expansions) does not.
197 .Sh SECURITY CONSIDERATIONS
198 Pathname generation may create output that is exponentially larger than the
201 Although this implementation detects command substitution reliably for
203 the attack surface remains fairly large.
204 Also, some other implementations
205 (such as older versions of this one)
206 may execute command substitutions even if