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


       #include <wordexp.h>

       int wordexp(const char *s, wordexp_t *p, int flags);

       void wordfree(wordexp_t *p);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       wordexp(), wordfree(): _XOPEN_SOURCE


       The  function  wordexp()  performs  a shell-like expansion of the string s and returns the
       result in the structure pointed to by p.  The data type wordexp_t is a structure  that  at
       least has the fields we_wordc, we_wordv, and we_offs.  The field we_wordc is a size_t that
       gives the number of words in the expansion of s.  The field we_wordv  is  a  char **  that
       points  to  the  array  of  words  found.   The  field we_offs of type size_t is sometimes
       (depending on flags, see below) used to indicate the number of  initial  elements  in  the
       we_wordv array that should be filled with NULLs.

       The  function  wordfree()  frees  the allocated memory again.  More precisely, it does not
       free its argument, but it frees the array we_wordv and the strings that points to.

   The string argument
       Since the expansion is the same  as  the  expansion  by  the  shell  (see  sh(1))  of  the
       parameters to a command, the string s must not contain characters that would be illegal in
       shell command parameters.  In particular, there must not be any unescaped newline or |, &,
       ;,  <,  >,  (, ), {, } characters outside a command substitution or parameter substitution

       If the argument s contains a word that starts with an unquoted comment character  #,  then
       it  is  unspecified  whether  that  word  and all following words are ignored, or the # is
       treated as a non-comment character.

   The expansion
       The expansion done consists of the following stages: tilde expansion (replacing  ~user  by
       user's  home  directory),  variable  substitution  (replacing  $FOO  by  the  value of the
       environment variable FOO), command substitution (replacing $(command) or `command` by  the
       output  of  command),  arithmetic  expansion,  field  splitting, wildcard expansion, quote

       The result of expansion of special parameters  ($@,  $*,  $#,  $?,  $-,  $$,  $!,  $0)  is

       Field  splitting is done using the environment variable $IFS.  If it is not set, the field
       separators are space, tab and newline.

   The output array
       The array we_wordv contains the words found, followed by a NULL.

   The flags argument
       The flag argument is a bitwise inclusive OR of the following values:

              Append the words found to the array resulting from a previous call.

              Insert we_offs initial NULLs in the array we_wordv.  (These are not counted in  the
              returned we_wordc.)

              Don't do command substitution.

              The  argument  p resulted from a previous call to wordexp(), and wordfree() was not
              called.  Reuse the allocated storage.

              Normally during command substitution stderr is redirected to /dev/null.  This  flag
              specifies that stderr is not to be redirected.

              Consider it an error if an undefined shell variable is expanded.


       In  case  of  success 0 is returned.  In case of error one of the following five values is

              Illegal occurrence of newline or one of |, &, ;, <, >, (, ), {, }.

              An undefined shell variable was referenced, and the  WRDE_UNDEF  flag  told  us  to
              consider this an error.

              Command substitution requested, but the WRDE_NOCMD flag told us to consider this an

              Out of memory.

              Shell syntax error, such as unbalanced parentheses or unmatched quotes.


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


       For an explanation of the terms used in this section, see attributes(7).

       │InterfaceAttributeValue                          │
       │wordexp()  │ Thread safety │ MT-Unsafe race:utent const:env │
       │           │               │ env sig:ALRM timer locale      │
       │wordfree() │ Thread safety │ MT-Safe                        │
       In the  above  table,  utent  in  race:utent  signifies  that  if  any  of  the  functions
       setutent(3),  getutent(3),  or  endutent(3) are used in parallel in different threads of a
       program, then data races  could  occur.   wordexp()  calls  those  functions,  so  we  use
       race:utent to remind users.


       POSIX.1-2001, POSIX.1-2008.


       The output of the following example program is approximately that of "ls [a-c]*.c".

       #include <stdio.h>
       #include <stdlib.h>
       #include <wordexp.h>

       main(int argc, char **argv)
           wordexp_t p;
           char **w;
           int i;

           wordexp("[a-c]*.c", &p, 0);
           w = p.we_wordv;
           for (i = 0; i < p.we_wordc; i++)
               printf("%s\n", w[i]);


       fnmatch(3), glob(3)


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                                            2017-09-15                                 WORDEXP(3)