DragonFly On-Line Manual Pages
FPUTS(3) DragonFly Library Functions Manual FPUTS(3)
fputs, fputs_unlocked, puts - output a line to a stream
Standard C Library (libc, -lc)
fputs(const char * restrict str, FILE * restrict stream);
fputs_unlocked(const char *str, FILE *stream);
puts(const char *str);
The function fputs() writes the string pointed to by str to the stream
pointed to by stream.
The fputs_unlocked() function is equivalent to fputs(), except that the
caller is responsible for locking the stream with flockfile(3) before
calling it. This function may be used to avoid the overhead of locking
the stream and to prevent races when multiple threads are operating on
the same stream.
The function puts() writes the string str, and a terminating newline
character, to the stream stdout.
The functions fputs() and puts() return a nonnegative integer on success
and EOF on error.
[EBADF] The stream argument is not a writable stream.
The functions fputs() and puts() may also fail and set errno for any of
the errors specified for the routines write(2).
ferror(3), fputws(3), putc(3), stdio(3)
The functions fputs() and puts() conform to ISO/IEC 9899:1990
DragonFly 5.9-DEVELOPMENT November 22, 2020 DragonFly 5.9-DEVELOPMENT
puts(n) Tcl Built-In Commands puts(n)
puts - Write to a channel
puts ?-nonewline? ?channelId? string
Writes the characters given by string to the channel given by
ChannelId must be an identifier for an open channel such as a Tcl
standard channel (stdout or stderr), the return value from an
invocation of open or socket, or the result of a channel creation
command provided by a Tcl extension. The channel must have been opened
If no channelId is specified then it defaults to stdout. Puts normally
outputs a newline character after string, but this feature may be
suppressed by specifying the -nonewline switch.
Newline characters in the output are translated by puts to platform-
specific end-of-line sequences according to the current value of the
-translation option for the channel (for example, on PCs newlines are
normally replaced with carriage-return-linefeed sequences. See the
fconfigure manual entry for a discussion on ways in which fconfigure
will alter output.
Tcl buffers output internally, so characters written with puts may not
appear immediately on the output file or device; Tcl will normally
delay output until the buffer is full or the channel is closed. You
can force output to appear immediately with the flush command.
When the output buffer fills up, the puts command will normally block
until all the buffered data has been accepted for output by the
operating system. If channelId is in nonblocking mode then the puts
command will not block even if the operating system cannot accept the
data. Instead, Tcl continues to buffer the data and writes it in the
background as fast as the underlying file or device can accept it. The
application must use the Tcl event loop for nonblocking output to work;
otherwise Tcl never finds out that the file or device is ready for more
output data. It is possible for an arbitrarily large amount of data to
be buffered for a channel in nonblocking mode, which could consume a
large amount of memory. To avoid wasting memory, nonblocking I/O
should normally be used in an event-driven fashion with the fileevent
command (do not invoke puts unless you have recently been notified via
a file event that the channel is ready for more output data).
Write a short message to the console (or wherever stdout is directed):
puts "Hello, World!"
Print a message in several parts:
puts -nonewline "Hello, "
Print a message to the standard error channel:
puts stderr "Hello, World!"
Append a log message to a file:
set chan [open my.log a]
set timestamp [clock format [clock seconds]]
puts $chan "$timestamp - Hello, World!"
file(n), fileevent(n), Tcl_StandardChannels(3)
channel, newline, output, write
Tcl 7.5 puts(n)