gen/wordexp.3

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  26 .\" $FreeBSD: src/lib/libc/gen/wordexp.3,v 1.6 2003/09/08 19:57:14 ru Exp $
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  28 .Dd December 27, 2002
  29 .Dt WORDEXP 3
  30 .Os
  31 .Sh NAME
  32 .Nm wordexp
  33 .Nd "perform shell-style word expansions"
  34 .Sh SYNOPSIS
  35 .In wordexp.h
  36 .Ft int
  37 .Fn wordexp "const char * restrict words" "wordexp_t * restrict we" "int flags"
  38 .Ft void
  39 .Fn wordfree "wordexp_t *we"
  40 .Sh DESCRIPTION
  41 The
  42 .Fn wordexp
  43 function performs shell-style word expansion on
  44 .Fa words
  45 and places the list of words into the
  46 .Va we_wordv
  47 member of
  48 .Fa we ,
  49 and the number of words into
  50 .Va we_wordc .
  51 .Pp
  52 The
  53 .Fa flags
  54 argument (see
  55 .Sx BUGS )
  56 is the bitwise inclusive OR of any of the following constants:
  57 .Bl -tag -width ".Dv WRDE_SHOWERR"
  58 .It Dv WRDE_APPEND
  59 Append the words to those generated by a previous call to
  60 .Fn wordexp .
  61 .It Dv WRDE_DOOFS
  62 As many
  63 .Dv NULL
  64 pointers as are specified by the
  65 .Va we_offs
  66 member of
  67 .Fa we
  68 are added to the front of
  69 .Va we_wordv .
  70 .It Dv WRDE_NOCMD
  71 Disallow command substitution in
  72 .Fa words .
  73 See the note in
  74 .Sx BUGS
  75 before using this.
  76 .It Dv WRDE_REUSE
  77 The
  78 .Fa we
  79 argument was passed to a previous successful call to
  80 .Fn wordexp
  81 but has not been passed to
  82 .Fn wordfree .
  83 The implementation may reuse the space allocated to it.
  84 .It Dv WRDE_SHOWERR
  85 Do not redirect shell error messages to
  86 .Pa /dev/null .
  87 .It Dv WRDE_UNDEF
  88 Report error on an attempt to expand an undefined shell variable.
  89 .El
  90 .Pp
  91 The
  92 .Vt wordexp_t
  93 structure is defined in
  94 .In wordexp.h
  95 as:
  96 .Bd -literal -offset indent
  97 typedef struct {
  98         size_t  we_wordc;       /* count of words matched */
  99         char    **we_wordv;     /* pointer to list of words */
 100         size_t  we_offs;        /* slots to reserve in we_wordv */
 101 } wordexp_t;
 102 .Ed
 103 .Pp
 104 The
 105 .Fn wordfree
 106 function frees the memory allocated by
 107 .Fn wordexp .
 108 .Sh RETURN VALUES
 109 The
 110 .Fn wordexp
 111 function returns zero if successful, otherwise it returns one of the following
 112 error codes:
 113 .Bl -tag -width ".Dv WRDE_NOSPACE"
 114 .It Dv WRDE_BADCHAR
 115 The
 116 .Fa words
 117 argument contains one of the following unquoted characters:
 118 .Aq newline ,
 119 .Ql | ,
 120 .Ql & ,
 121 .Ql \&; ,
 122 .Ql < ,
 123 .Ql > ,
 124 .Ql \&( ,
 125 .Ql \&) ,
 126 .Ql { ,
 127 .Ql } .
 128 .It Dv WRDE_BADVAL
 129 An attempt was made to expand an undefined shell variable and
 130 .Dv WRDE_UNDEF
 131 is set in
 132 .Fa flags .
 133 .It Dv WRDE_CMDSUB
 134 An attempt was made to use command substitution and
 135 .Dv WRDE_NOCMD
 136 is set in
 137 .Fa flags .
 138 .It Dv WRDE_NOSPACE
 139 Not enough memory to store the result.
 140 .It Dv WRDE_SYNTAX
 141 Shell syntax error in
 142 .Fa words .
 143 .El
 144 .Pp
 145 The
 146 .Fn wordfree
 147 function returns no value.
 148 .Sh EXAMPLES
 149 Invoke the editor on all
 150 .Pa .c
 151 files in the current directory
 152 and
 153 .Pa /etc/motd
 154 (error checking omitted):
 155 .Bd -literal -offset indent
 156 wordexp_t we;
 157
 158 wordexp("${EDITOR:-vi} *.c /etc/motd", &we, 0);
 159 execvp(we->we_wordv[0], we->we_wordv);
 160 .Ed
 161 .Sh SEE ALSO
 162 .Xr sh 1 ,
 163 .Xr fnmatch 3 ,
 164 .Xr glob 3 ,
 165 .Xr popen 3 ,
 166 .Xr system 3
 167 .Sh BUGS
 168 This version of
 169 .Fn workexp
 170 ignores the value of the
 171 .Fa flags
 172 argument.
 173 .Sh COPYRIGHT
 174 Copyright 1995-2002 University Corporation for Atmospheric Research/Unidata
 175 .Pp
 176 Portions of this software were developed by the Unidata Program at the
 177 University Corporation for Atmospheric Research.