WORDEXP(3)		   Linux Programmers Manual		   WORDEXP(3)



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

SYNOPSIS
       #include 

       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 pre
       cisely, 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 par
       ticular, there must not be any non-escaped newline or |, &, ;, <, >, (,
       ),  {, } characters outside a command substitution or parameter substi
       tution 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  users  home  directory),	variable substitution
       (replacing $FOO by the value of the environment variable FOO),  command
       substitution  (replacing  $(command) or `command` by the output of com
       mand), 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
	      Dont do command substitution.

       WRDE_REUSE
	      The  argument  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 redi
	      rected.

       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 follow
       ing 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.

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

       #include 
       #include 
       #include 

       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);
       }

SEE ALSO
       fnmatch(3), glob(3)

COLOPHON
       This  page  is  part of release 3.05 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/.



				  2008-07-14			    WORDEXP(3)