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(libc.info)Calling Wordexp

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Calling `wordexp'
-----------------

   All the functions, constants and data types for word expansion are
declared in the header file `wordexp.h'.

   Word expansion produces a vector of words (strings).  To return this
vector, `wordexp' uses a special data type, `wordexp_t', which is a
structure.  You pass `wordexp' the address of the structure, and it
fills in the structure's fields to tell you about the results.

 - Data Type: wordexp_t
     This data type holds a pointer to a word vector.  More precisely,
     it records both the address of the word vector and its size.

    `we_wordc'
          The number of elements in the vector.

    `we_wordv'
          The address of the vector.  This field has type `char **'.

    `we_offs'
          The offset of the first real element of the vector, from its
          nominal address in the `we_wordv' field.  Unlike the other
          fields, this is always an input to `wordexp', rather than an
          output from it.

          If you use a nonzero offset, then that many elements at the
          beginning of the vector are left empty.  (The `wordexp'
          function fills them with null pointers.)

          The `we_offs' field is meaningful only if you use the
          `WRDE_DOOFFS' flag.  Otherwise, the offset is always zero
          regardless of what is in this field, and the first real
          element comes at the beginning of the vector.

 - Function: int wordexp (const char *WORDS, wordexp_t
          *WORD-VECTOR-PTR, int FLAGS)
     Perform word expansion on the string WORDS, putting the result in
     a newly allocated vector, and store the size and address of this
     vector into `*WORD-VECTOR-PTR'.  The argument FLAGS is a
     combination of bit flags; see Note: Flags for Wordexp, for
     details of the flags.

     You shouldn't use any of the characters `|&;<>' in the string
     WORDS unless they are quoted; likewise for newline.  If you use
     these characters unquoted, you will get the `WRDE_BADCHAR' error
     code.  Don't use parentheses or braces unless they are quoted or
     part of a word expansion construct.  If you use quotation
     characters `'"`', they should come in pairs that balance.

     The results of word expansion are a sequence of words.  The
     function `wordexp' allocates a string for each resulting word, then
     allocates a vector of type `char **' to store the addresses of
     these strings.  The last element of the vector is a null pointer.
     This vector is called the "word vector".

     To return this vector, `wordexp' stores both its address and its
     length (number of elements, not counting the terminating null
     pointer) into `*WORD-VECTOR-PTR'.

     If `wordexp' succeeds, it returns 0.  Otherwise, it returns one of
     these error codes:

    `WRDE_BADCHAR'
          The input string WORDS contains an unquoted invalid character
          such as `|'.

    `WRDE_BADVAL'
          The input string refers to an undefined shell variable, and
          you used the flag `WRDE_UNDEF' to forbid such references.

    `WRDE_CMDSUB'
          The input string uses command substitution, and you used the
          flag `WRDE_NOCMD' to forbid command substitution.

    `WRDE_NOSPACE'
          It was impossible to allocate memory to hold the result.  In
          this case, `wordexp' can store part of the results--as much
          as it could allocate room for.

    `WRDE_SYNTAX'
          There was a syntax error in the input string.  For example,
          an unmatched quoting character is a syntax error.

 - Function: void wordfree (wordexp_t *WORD-VECTOR-PTR)
     Free the storage used for the word-strings and vector that
     `*WORD-VECTOR-PTR' points to.  This does not free the structure
     `*WORD-VECTOR-PTR' itself--only the other data it points to.