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

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.

   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 context.

       If the argument s contains a word that starts with an unquoted comment character #, then it is unspecified whether that word and  all  fol-
       lowing 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 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 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.

EXAMPLE

       The output of the following example program 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
", w[i]);
	   wordfree(&p);
	   exit(EXIT_SUCCESS);
       }

SEE ALSO

       fnmatch(3), glob(3)

COLOPHON

       This  page is part of release 3.27 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)