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NAME

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

SYNOPSIS

       #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

DESCRIPTION

       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.

   Example
       First  a  small  example.   The output is approximately that of "ls [a-
       c]*.c".

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

       int
       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]);
           wordfree(&p);
           exit(EXIT_SUCCESS);
       }

   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 non-escaped newline or |, &, ;, <, >,
       (, ), {, } characters  outside  a  command  substitution  or  parameter
       substitution context.

       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 removal.

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

       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:

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

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

       WRDE_NOCMD
              Don’t do command substitution.

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

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

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

RETURN VALUE

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

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

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

       WRDE_CMDSUB
              Command  substitution  occurred, and the WRDE_NOCMD flag told us
              to consider this an error.

       WRDE_NOSPACE
              Out of memory.

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

VERSIONS

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

CONFORMING TO

       POSIX.1-2001

SEE ALSO

       fnmatch(3), glob(3)

COLOPHON

       This  page  is  part of release 3.01 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2008-06-14                        WORDEXP(3)