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3.18 Primitive character I/O

See section 3.2 for an overview of supported character representations.

nl
Write a newline character to the current output stream. On Unix systems nl/0 is equivalent to put(10).
nl(+Stream)
Write a newline to Stream.
put(+Char)
Write Char to the current output stream, Char is either an integer-expression evaluating to an ASCII value (0 =<Char =< 255) or an atom of one character.
put(+Stream, +Char)
Write Char to Stream.
put_byte(+Byte)
Alias for put/1.
put_byte(+Stream, +Byte)
Alias for put/2
put_char(+Char)
Alias for put_char/1.
put(+Stream, +Char)
Alias for put/2
put_code(+Code)
Alias for put/1.
put_code(+Stream, +Code)
Alias for put/2
tab(+Amount)
Writes Amount spaces on the current output stream. Amount should be an expression that evaluates to a positive integer (see section 3.26).
tab(+Stream, +Amount)
Writes Amount spaces to Stream.
flush_output
Flush pending output on current output stream. flush_output/0 is automatically generated by read/1 and derivatives if the current input stream is user and the cursor is not at the left margin.
flush_output(+Stream)
Flush output on the specified stream. The stream must be open for writing.
ttyflush
Flush pending output on stream user. See also flush_output/[0,1].
get_byte(-Byte)
Read the current input stream and unify the next byte with Byte (an integer between 0 and 255. Byte is unified with -1 on end of file.
get_byte(+Stream, -Byte)
Read the next byte from Stream.
get_code(-Code)
Read the current input stream and unify Code with the character code of the next character. Char is unified with -1 on end of file. See also get_char/1.
get_code(+Stream, -Code)
Read the next character-code from Stream.
get_char(-Char)
Read the current input stream and unify Char with the next character as a one-character-atom. See also atom_chars/2. On end-of-file, Char is unified to the atom end_of_file.
get_char(+Stream, -Char)
Unify Char with the next character from Stream as a one-character-atom. See also get_char/2, get_byte/2 and get_code/2.
get0(-Char)
Edinburgh version of the ISO get_byte/1 predicate.
get0(+Stream, -Char)
Edinburgh version of the ISO get_byte/2 predicate.
get(-Char)
Read the current input stream and unify the next non-blank character with Char. Char is unified with -1 on end of file.
get(+Stream, -Char)
Read the next non-blank character from Stream.
peek_byte(-Byte)
Reads the next input byte like get_byte/1, but does not remove it from the input stream.
peek_byte(+Stream, -Byte)
Reads the next input byte like get_byte/2, but does not remove it from the stream.
peek_code(-Code)
Reads the next input code like get_code/1, but does not remove it from the input stream.
peek_code(+Stream, -Code)
Reads the next input code like get_code/2, but does not remove it from the stream.
peek_char(-Char)
Reads the next input character like get_char/1, but does not remove it from the input stream.
peek_char(+Stream, -Char)
Reads the next input character like get_char/2, but does not remove it from the stream.
skip(+Char)
Read the input until Char or the end of the file is encountered. A subsequent call to get0/1 will read the first character after Char.
skip(+Stream, +Char)
Skip input (as skip/1) on Stream.
get_single_char(-Char)
Get a single character from input stream `user' (regardless of the current input stream). Unlike get0/1 this predicate does not wait for a return. The character is not echoed to the user's terminal. This predicate is meant for keyboard menu selection etc. If SWI-Prolog was started with the -tty option this predicate reads an entire line of input and returns the first non-blank character on this line, or the ASCII code of the newline (10) if the entire line consisted of blank characters.
at_end_of_stream
Succeeds after the last character of the current input stream has been read. Also succeeds if there is no valid current input stream.
at_end_of_stream(+Stream)
Succeeds after the last character of the named stream is read, or Stream is not a valid input stream.
copy_stream_data(+StreamIn, +StreamOut, +Len)
Copy Len bytes from stream StreamIn to StreamOut.
copy_stream_data(+StreamIn, +StreamOut)
Copy data all (remaining) data from stream StreamIn to StreamOut.