QUOTE(2)                                                 QUOTE(2)

     NAME
          quotestrdup, quoterunestrdup, unquotestrdup,
          unquoterunestrdup, quotestrconv, quoterunestrconv,
          quotefmtinstall, doquote - quoted character strings

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

          char *quotestrdup(char *s)

          Rune *quoterunestrdup(Rune *s)

          char *unquotestrdup(char *s)

          Rune *unquoterunestrdup(Rune *s)

          int quotestrconv(va_list *arg, Fconv *fp)

          int quoterunestrconv(va_list *arg, Fconv *fp)

          void quotefmtinstall(void)

          int (*doquote)(int c)

     DESCRIPTION
          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)).

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

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     QUOTE(2)                                                 QUOTE(2)

          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.

          Quotestrconv and quoterunestrconv are print(2) formatting
          routines 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 because they use malloc, which no
          other standard format requires.)  In <libc.h> there are
          #pragma statements so the compiler can type-check uses of %q
          and %Q in print(2) format strings.

     SOURCE
          /sys/src/libc/port/quote.c
          /sys/src/libc/port/printquote.c

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

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