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WORDEXP(3)                 Library Functions Manual                 WORDEXP(3)

NAME
     wordexp - perform shell-style word expansions

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <wordexp.h>

     int
     wordexp(const char * restrict words, wordexp_t * restrict pwordexp,
         int flags);

     void
     wordfree(wordexp_t *pwordexp);

DESCRIPTION
     The wordexp() function performs shell-style word expansion on words and
     places the list of expanded words into the structure pointed to by
     pwordexp.

     The flags argument is the bitwise inclusive OR of any of the following
     constants:

     WRDE_APPEND       Append the words to those generated by a previous call
                       to wordexp().

     WRDE_DOOFFS       As many NULL pointers as are specified by the we_offs
                       member of we are added to the front of we_wordv.

     WRDE_NOCMD        Disallow command substitution in words.  See the note
                       in BUGS before using this.

     WRDE_REUSE        The we argument was passed to a previous successful
                       call to wordexp() but has not been passed to
                       wordfree().  The implementation may reuse the space
                       allocated to it.

     WRDE_SHOWERR      Do not redirect shell error messages to /dev/null.

     WRDE_UNDEF        Report error on an attempt to expand an undefined shell
                       variable.

     The structure type wordexp_t includes the following members:

           size_t  we_wordc
           char    **we_wordv
           size_t  we_offs

     The we_wordc member is the count of generated words.

     The we_wordv member points to a list of pointers to expanded words.

     The we_offs member is the number of slots to reserve at the beginning of
     the we_wordv member.

     It is the caller's responsibility to allocate the storage pointed to by
     pwordexp.  The wordexp() function allocates other space as needed,
     including memory pointed to by the we_wordv member.

     The wordfree() function frees the memory allocated by wordexp().

IMPLEMENTATION NOTES
     The wordexp() function is implemented as a wrapper around the
     undocumented wordexp shell built-in command.

RETURN VALUES
     The wordexp() function returns zero if successful, otherwise it returns
     one of the following error codes:

     WRDE_BADCHAR      The words argument contains one of the following
                       unquoted characters: <newline>, `|', `&', `;', `<',
                       `>', `(', `)', `{', `}'.

     WRDE_BADVAL       An attempt was made to expand an undefined shell
                       variable and WRDE_UNDEF is set in flags.

     WRDE_CMDSUB       An attempt was made to use command substitution and
                       WRDE_NOCMD is set in flags.

     WRDE_NOSPACE      Not enough memory to store the result.

     WRDE_SYNTAX       Shell syntax error in words.

     WRDE_ERRNO        An internal error occurred and errno is set to indicate
                       the error.

     The wordfree() function returns no value.

ENVIRONMENT
     IFS      Field separator.

EXAMPLES
     Invoke the editor on all .c files in the current directory and /etc/motd
     (error checking omitted):

           wordexp_t we;

           wordexp("${EDITOR:-vi} *.c /etc/motd", &we, 0);
           execvp(we->we_wordv[0], we->we_wordv);

DIAGNOSTICS
     Diagnostic messages from the shell are written to the standard error
     output if WRDE_SHOWERR is set in flags.

SEE ALSO
     sh(1), fnmatch(3), glob(3), popen(3), system(3)

STANDARDS
     The wordexp() and wordfree() functions conform to IEEE Std 1003.1-2001
     ("POSIX.1").  Their first release was in IEEE Std 1003.2-1992
     ("POSIX.2").  The return value WRDE_ERRNO is an extension.

BUGS
     Do not pass untrusted user data to wordexp(), regardless of whether the
     WRDE_NOCMD flag is set.  The wordexp() function attempts to detect input
     that would cause commands to be executed before passing it to the shell
     but it does not use the same parser so it may be fooled.

NetBSD 10.99                     July 13, 2004                    NetBSD 10.99