QUOTE(2)                                                 QUOTE(2)

          quotestrdup, quoterunestrdup, unquotestrdup,
          unquoterunestrdup, quotestrfmt, quoterunestrfmt,
          quotefmtinstall, doquote, needsrcquote - quoted character

          #include <u.h>
          #include <libc.h>

          char *quotestrdup(char *s)

          Rune *quoterunestrdup(Rune *s)

          char *unquotestrdup(char *s)

          Rune *unquoterunestrdup(Rune *s)

          int quotestrfmt(Fmt*)

          int quoterunestrfmt(Fmt*)

          void quotefmtinstall(void)

          int (*doquote)(int c)

          int needsrcquote(int c)

          These routines manipulate character strings, either adding
          or removing quotes as necessary.  In the quoted form, the
          strings are in the style of rc(1), with single quotes sur-
          rounding the string.  Embedded single quotes are indicated
          by a doubled single quote.  For instance,

               Don't worry!

          when quoted becomes

               'Don''t worry!'

          The empty string is represented by two quotes, ''.

          The first four functions act as variants of strdup (see
          strcat(2)). Each returns a freshly allocated copy of the
          string, created using malloc(2). Quotestrdup returns a
          quoted copy of s, while unquotestrdup returns a copy of s
          with the quotes evaluated.  The rune versions of these func-
          tions do the same for strings (see runestrcat(2)).

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     QUOTE(2)                                                 QUOTE(2)

          The string returned by quotestrdup or quoterunestrdup has
          the following properties:

          1.   If the original string s is empty, the returned string
               is ''.

          2.   If s contains no quotes, blanks, or control characters,
               the returned string is identical to s.

          3.   If s needs quotes to be added, the first character of
               the returned string will be a quote.  For example,
               hello world becomes 'hello world' not hello' 'world.

          The function pointer doquote is nil by default.  If it is
          non-nil, characters are passed to that function to see if
          they should be quoted.  This mechanism allows programs to
          specify that characters other than blanks, control charac-
          ters, or quotes be quoted.  Regardless of the return value
          of *doquote, blanks, control characters, and quotes are
          always quoted.  Needsrcquote is provided as a doquote func-
          tion that flags any character special to rc(1).

          Quotestrfmt and quoterunestrfmt are print(2) formatting rou-
          tines that produce quoted strings as output.  They may be
          installed by hand, but quotefmtinstall installs them under
          the standard format characters q and Q.  (They are not
          installed automatically.)  If the format string includes the
          alternate format character #, for example %#q, the printed
          string will always be quoted; otherwise quotes will only be
          provided if necessary to avoid ambiguity.  In <libc.h> there
          are #pragma statements so the compiler can type-check uses
          of %q and %Q in print(2) format strings.


          rc(1), malloc(2), print(2), strcat(2)

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