putc(3S) putc(3S)
NAME
putc(), putchar(), fputc(), putw() - put character or word on a stream
SYNOPSIS
Obsolescent Interfaces
DESCRIPTION
Writes the character
c onto the output stream at the position where the file pointer, if defined, is pointing. is defined as and are defined
both as macros and as functions.
Same as but is a function rather than a macro, and can therefore be used as an argument. runs more slowly than but takes less space
per invocation, and its name can be passed as an argument to a function.
Writes the word (i.e.,
in C) w to the output stream (at the position at which the file pointer, if defined, is pointing). The size of a word is
the size of an integer and varies from machine to machine. neither assumes nor causes special alignment in the file.
Output streams, with the exception of the standard error stream are by default buffered if the output refers to a file and line-buffered if
the output refers to a terminal. The standard error output stream, is by default unbuffered, but use of (see fopen(3S)) causes it to
become buffered or line-buffered. or (see setbuf(3S)) can be used to change the stream's buffering strategy. put character on a stream.
Obsolescent Interfaces
put character or word on a stream.
APPLICATION USAGE
After or is applied to a stream, the stream becomes byte-oriented (see orientation(5)).
RETURN VALUE
On success, and each return the value they have written. On failure, they return the constant EOF, set the error indicator for the stream,
and set to indicate the error.
On success, and return 0. Otherwise, a non-zero value is returned, the error indicator for the stream is set, and is set to indicate the
error.
ERRORS
and fail if, either the stream is unbuffered or stream's buffer needed to be flushed causing an underlying call to be invoked, and:
[EAGAIN] The flag is set for the file descriptor underlying stream and the process would be delayed in the write operation.
[EBADF] The file descriptor underlying stream is not a valid file descriptor open for writing.
[EFBIG] An attempt was made to write to a file that exceeds the process's file size limit or the maximum file size (see
ulimit(2)).
[EINTR] A signal was caught during the system call.
[EIO] A physical I/O error has occurred, or the process is in a background process group and is attempting to write to its
controlling terminal, is set, the process is neither ignoring nor blocking the signal, and the process group of the
process is orphaned.
[ENOSPC] There was no free space remaining on the device containing the file.
[EPIPE] An attempt is made to write to a pipe or FIFO that is not open for reading by any process. A signal is also sent to
the process.
Additional values can be set by the underlying function (see write(2)).
WARNINGS
The and routines are implemented as both library functions and macros. The macro versions, which are used by default, are defined in To
obtain the library function either use a to remove the macro definition or, if compiling in ANSI-C mode, enclose the function name in
parentheses or use the function address. The following example illustrates each of these methods:
...
...
...
...
Line buffering may cause confusion or malfunctioning of programs that use standard I/O routines but use themselves to read from standard
input. When a large amount of computation is done after printing part of a line on an output terminal, it is necessary to (see fclose(3S))
the standard output before beginning the computation.
The macro version of incorrectly treats the argument stream with side effects. In particular, the following call may not work as expected:
The function version of or should be used instead.
Because of possible differences in word length and byte ordering, files written using are machine-dependent, and may not be readable by on
a different processor.
is an obsolescent interface supported only for compatibility with existing DCE applications. New multithreaded applications should use and
Reentrant Interfaces
If is defined, the locked versions of the library functions for and are used by default.
SEE ALSO
fclose(3S), ferror(3S), flockfile(3S), fopen(3S), getc(3S), fread(3S), printf(3S), puts(3S), setbuf(3S), orientation(5), thread_safety(5).
STANDARDS CONFORMANCE
putc(3S)