6.1.4 Character I/O

nl

ISO
A new line character is sent to the current output stream.

nl(+Stream)

ISO
A new line character is sent to the designated output stream.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open stream
  • existence_error(stream,Stream_or_alias)

get_char(+Stream_or_alias,?Char)

ISO
Unifies Char with the next ASCII character from Stream_or_alias, advancing the position of the stream. Char is unified with -1 if an end of file condition is detected.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Char is not a variable or character.
  • domain_error(character_or_variable,Char)

get_char(?Char)

ISO
Behaves as get_char/2, but reads from the current input stream.

Error Cases

• Char is not a variable or character.
  • domain_error(character_or_variable,Char)

get_code(+Stream_or_alias,?Code)

ISO
Code unifies with the ASCII code of the next character from Stream_or_alias. The position of the stream is advanced.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Code is not a variable or character code
  • domain_error(character_code_or_variable,Code)

get_code(?Code)

ISO
Behaves as get_code/2, but reads from the current input stream.

Error Cases

• Code is not a variable or character code
  • domain_error(character_code_or_variable,Code)

get0(?N)

N is the ASCII code of the next character read from the current input stream (regarded as a text stream). If the current input stream reaches its end of file, a -1 is returned. This predicate does not check for errors, so that it is faster (and less safe) than, e.g. get_code/1.

get(?N)

N is the ASCII code of the next non-blank printable character from the current input stream (regarded as a text stream). If the current input stream reaches its end of file, a -1 is returned.

peek_char(+Stream_or_alias,?Char)

ISO
Char is the next ASCII character from Stream_or_alias. The position in Stream_or_alias is unchanged. Char is unified with -1 if an end of file condition is detected.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Char is not a variable or character.
  • domain_error(character_or_variable,Char)

peek_char(?Char)

ISO
Char is the next ASCII character from the current input stream. The position in the current input stream is unchanged. Char is unified with -1 if an end of file condition is detected.

Error Cases

• Char is not a variable or character.
  • domain_error(character_or_variable,Char)

peek_code(+Stream_or_alias,?Code)

ISO
Code is the next ASCII coder from Stream_or_alias. The position in Stream_or_alias is unchanged. Code is unified with -1 if an end of file condition is detected.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Code is not a variable or character.
  • domain_error(character_code_or_variable,Code)

peek_code(?Code)

ISO
Behaves as peek_code/1, but the current input stream is used.

Error Cases

• Char is not a variable or character.
  • domain_error(character_code_or_variable,Code)

put_char(+Stream,+Char)

ISO
Puts the ASCII character Char to Stream_or_alias.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Char is a not a character
  • type_error(character,Char)

put_char(+Char)

ISO
Puts the ASCII code of the character Char to the current output stream.

Error Cases

• Code is a not a character.
  • type_error(character,Char)

put_code(+Stream,+Code)

ISO
Puts the ASCII code of the character Char to Stream_or_alias.

Error Cases

• Stream_or_alias is not instantiated to a stream term or alias.
  • domain_error(stream_or_alias,Stream_or_alias)
• Stream_or_alias is not associated with an open input stream
  • existence_error(stream,Stream_or_alias)
• Code is a not a character code
  • type_error(character_code,Code)

put_code(+Code)

ISO
Puts the ASCII code Code to the current output stream. Error Cases

• Code is a not a character code.
  • type_error(character_code,Code)

put(+Code)

Puts the ASCII character code N to the current output stream.

Error Cases

• Code is a not a character code.
  • type_error(character_code,Code)

tab(+N)

Puts N spaces to the current output stream.

Error Cases

• Code is a not a positiveInteger
  • domain_error(positiveInteger,Code)