Speccy ClassiX 1998/Speccy ClassiX 98.iso/amiga_system/the_aminet/dev/gcc/ixemulsdk.lha/man/cat3/vis.0

Text File | 1992-08-10 | 6KB | 133 lines

VIS(3)                     UNIX Programmer's Manual                     VIS(3)

NNAAMMEE
     vviiss - visually encode characters

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<vviiss..hh>>

     _c_h_a_r _*
     vviiss(_c_h_a_r _*_d_s_t, _c_h_a_r _c, _i_n_t _f_l_a_g, _c_h_a_r _n_e_x_t_c)

     _i_n_t
     ssttrrvviiss(_c_h_a_r _*_d_s_t, _c_h_a_r _*_s_r_c, _i_n_t _f_l_a_g)

     _i_n_t
     ssttrrvviissxx(_c_h_a_r _*_d_s_t, _c_h_a_r _*_s_r_c, _i_n_t _l_e_n, _i_n_t _f_l_a_g)

DDEESSCCRRIIPPTTIIOONN
     The vviiss() function copies into _d_s_t a string which represents the charac¡
     ter _c. If _c needs no encoding, it is copied in unaltered.  The string is
     null terminated, and a pointer to the end of the string is returned.  The
     maximum length of any encoding is four characters (not including the
     trailing NULL); thus, when encoding a set of characters into a buffer,
     the size of the buffer should be four times the number of characters en¡
     coded, plus one for the trailing NULL. The flag parameter is used for al¡
     tering the default range of characters considered for encoding and for
     altering the visual representation.  The additional character, _n_e_x_t_c, is
     only used when selecting the VIS_CSTYLE encoding format (explained be¡
     low).

     The ssttrrvviiss() and ssttrrvviissxx() functions copy into _d_s_t a visual representa¡
     tion of the string _s_r_c. The ssttrrvviiss() function encodes characters from _s_r_c
     up to the first NULL. The ssttrrvviissxx() function encodes exactly _l_e_n charac¡
     ters from _s_r_c (this is useful for encoding a block of data that may con¡
     tain NULL's). Both forms NULL terminate _d_s_t. The size of _d_s_t must be four
     times the number of characters encoded from _s_r_c (plus one for the NULL).
     Both forms return the number of characters in dst (not including the
     trailing NULL).

     The encoding is a unique, invertible representation comprised entirely of
     graphic characters; it can be decoded back into the original form using
     the unvis(3) or strunvis(3) functions.

     There are two parameters that can be controlled: the range of characters
     that are encoded, and the type of representation used.  By default, all
     non¡graphic characters.  except space, tab, and newline are encoded.
     (See isgraph(3).)  The following flags alter this:

     VIS_SP      Also encode space.

     VIS_TAB
                 Also encode tab.

     VIS_NL      Also encode newline.

     VIS_WHITE   Synonym for VIS_SP | VIS_TAB | VIS_NL.

     VIS_SAFE    Only encode "unsafe" characters.  Unsafe means control char¡
                 acters which may cause common terminals to perform unexpected
                 functions.  Currently this form allows space, tab, newline,
                 backspace, bell, and return ¡ in addition to all graphic
                 characters ¡ unencoded.


     There are three forms of encoding.  All forms use the backslash character
     `\' to introduce a special sequence; two backslashes are used to repre¡
     sent a real backslash.  These are the visual formats:

     (default)   Use an `M' to represent meta characters (characters with the
                 8th bit set), and use carat `^' to represent control charac¡
                 ters see (iscntrl(3)).  The following formats are used:

                 \^C    Represents the control character `C'. Spans characters
                        `\000' through `\037', and `\177' (as `\^?').

                 \M¡C   Represents character `C' with the 8th bit set.  Spans
                        characters `\241' through `\376'.

                 \M^C   Represents control character `C' with the 8th bit set.
                        Spans characters `\200' through `\237', and `\377' (as
                        `\M^?').

                 \040   Represents ASCII space.

                 \240   Represents Meta¡space.

     VIS_CSTYLE  Use C¡style backslash sequences to represent standard non¡
                 printable characters.  The following sequences are used to
                 represent the indicated characters:

                       \a ¡ BEL (007)
                       \b ¡ BS (010)
                       \f ¡ NP (014)
                       \n ¡ NL (012)
                       \r ¡ CR (015)
                       \t ¡ HT (011)
                       \v ¡ VT (013)
                       \0 ¡ NUL (000)

                 When using this format, the nextc parameter is looked at to
                 determine if a NULL character can be encoded as `\0' instead
                 of `\000'. If _n_e_x_t_c is an octal digit, the latter representa¡
                 tion is used to avoid ambiguity.

     VIS_OCTAL   Use a three digit octal sequence.  The form is `\ddd' where _d
                 represents an octal digit.

     There is one additional flag, VIS_NOSLASH, which inhibits the doubling of
     backslashes and the backslash before the default format (that is, control
     characters are represented by `^C' and meta characters as `M¡C'). With
     this flag set, the encoding is ambiguous and non¡invertible.

SSEEEE AALLSSOO
     unvis(1),  unvis(3) strunvis(3)

HHIISSTTOORRYY
     These functions are currently under development.

BSD Experimental                April 19, 1991                               2