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 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  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\n", w[i]);
           wordfree(&p);
           exit(EXIT_SUCCESS);
       }

SEE ALSO

       fnmatch(3), glob(3)

COLOPHON

       This page is part of release 3.54 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)