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)