1WORDEXP(3)                 Linux Programmer's Manual                WORDEXP(3)
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NAME

6       wordexp, wordfree - perform word expansion like a posix-shell
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SYNOPSIS

9       #include <wordexp.h>
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11       int wordexp(const char *s, wordexp_t *p, int flags);
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13       void wordfree(wordexp_t *p);
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15   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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17       wordexp(), wordfree(): _XOPEN_SOURCE
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DESCRIPTION

20       The  function wordexp() performs a shell-like expansion of the string s
21       and returns the result in the structure pointed to by p.  The data type
22       wordexp_t  is  a  structure  that  at  least  has  the fields we_wordc,
23       we_wordv, and we_offs.  The field we_wordc is a size_t that  gives  the
24       number of words in the expansion of s.  The field we_wordv is a char **
25       that points to the array of words found.  The  field  we_offs  of  type
26       size_t  is  sometimes  (depending on flags, see below) used to indicate
27       the number of initial elements in the we_wordv  array  that  should  be
28       filled with NULLs.
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30       The  function  wordfree()  frees the allocated memory again.  More pre‐
31       cisely, it does not free its argument, but it frees the array  we_wordv
32       and the strings that points to.
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34   The string argument
35       Since  the  expansion  is  the  same as the expansion by the shell (see
36       sh(1)) of the parameters to a command, the string s  must  not  contain
37       characters  that would be illegal in shell command parameters.  In par‐
38       ticular, there must not be any non-escaped newline or |, &, ;, <, >, (,
39       ),  {, } characters outside a command substitution or parameter substi‐
40       tution context.
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42       If the argument s contains a word that starts with an unquoted  comment
43       character #, then it is unspecified whether that word and all following
44       words are ignored, or the # is treated as a non-comment character.
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46   The expansion
47       The expansion done consists of the following  stages:  tilde  expansion
48       (replacing  ~user  by  user's  home  directory),  variable substitution
49       (replacing $FOO by the value of the environment variable FOO),  command
50       substitution  (replacing  $(command) or `command` by the output of com‐
51       mand), arithmetic expansion, field splitting, wildcard expansion, quote
52       removal.
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54       The  result of expansion of special parameters ($@, $*, $#, $?, $-, $$,
55       $!, $0) is unspecified.
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57       Field splitting is done using the environment variable $IFS.  If it  is
58       not set, the field separators are space, tab and newline.
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60   The output array
61       The array we_wordv contains the words found, followed by a NULL.
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63   The flags argument
64       The flag argument is a bitwise inclusive OR of the following values:
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66       WRDE_APPEND
67              Append  the  words  found to the array resulting from a previous
68              call.
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70       WRDE_DOOFFS
71              Insert we_offs initial NULLs in the array we_wordv.  (These  are
72              not counted in the returned we_wordc.)
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74       WRDE_NOCMD
75              Don't do command substitution.
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77       WRDE_REUSE
78              The  argument  p resulted from a previous call to wordexp(), and
79              wordfree() was not called.  Reuse the allocated storage.
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81       WRDE_SHOWERR
82              Normally during command substitution  stderr  is  redirected  to
83              /dev/null.   This  flag specifies that stderr is not to be redi‐
84              rected.
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86       WRDE_UNDEF
87              Consider it an error if an undefined shell variable is expanded.
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RETURN VALUE

90       In case of success 0 is returned.  In case of error one of the  follow‐
91       ing five values is returned.
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93       WRDE_BADCHAR
94              Illegal  occurrence of newline or one of |, &, ;, <, >, (, ), {,
95              }.
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97       WRDE_BADVAL
98              An undefined shell variable was referenced, and  the  WRDE_UNDEF
99              flag told us to consider this an error.
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101       WRDE_CMDSUB
102              Command  substitution  occurred, and the WRDE_NOCMD flag told us
103              to consider this an error.
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105       WRDE_NOSPACE
106              Out of memory.
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108       WRDE_SYNTAX
109              Shell syntax error, such as unbalanced parentheses or  unmatched
110              quotes.
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VERSIONS

113       wordexp() and wordfree() are provided in glibc since version 2.1.
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CONFORMING TO

116       POSIX.1-2001.
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EXAMPLE

119       The  output  of  the following example program is approximately that of
120       "ls [a-c]*.c".
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122       #include <stdio.h>
123       #include <stdlib.h>
124       #include <wordexp.h>
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126       int
127       main(int argc, char **argv)
128       {
129           wordexp_t p;
130           char **w;
131           int i;
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133           wordexp("[a-c]*.c", &p, 0);
134           w = p.we_wordv;
135           for (i = 0; i < p.we_wordc; i++)
136               printf("%s\n", w[i]);
137           wordfree(&p);
138           exit(EXIT_SUCCESS);
139       }
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SEE ALSO

142       fnmatch(3), glob(3)
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COLOPHON

145       This page is part of release 3.22 of the Linux  man-pages  project.   A
146       description  of  the project, and information about reporting bugs, can
147       be found at http://www.kernel.org/doc/man-pages/.
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151                                  2008-07-14                        WORDEXP(3)
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