Guardian Native C Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

Guardian Native C Library Calls (n - r) putchar(3)
NAME
putchar - Writes a byte to the standard output stream
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRTLSRL
G-series native OSS processes: /G/system/sysnn/zcrtlsrl
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCRTLDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcrtldll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycrtldll
SYNOPSIS
#include <stdio.h>
int putchar(
int c);
PARAMETERS
c Specifies the character to be written.
DESCRIPTION
The putchar( ) macro writes the character c to the standard output stream. The character is writ-
ten at the position at which the file pointer is currently pointing, if defined.
With the exception of stderr, output streams are, by default, buffered if they refer to files, or line
buffered if they refer to terminals. The standard error output stream, stderr, is unbuffered by
default, but using the freopen( ) function causes it to become buffered or line buffered. Use the
setbuf() function to change the stream buffering strategy.
When an output stream is unbuffered, information is queued for writing on the destination file or
terminal as soon as it is written. When an output stream is buffered, many characters are saved
and written as a block. When an output stream is line-buffered, each line of output is queued for
writing on the destination terminal as soon as the line is completed (that is, as soon as a newline
character is written or terminal input is requested).
The st_ctime and st_mtime fields of the file are marked for update between the successful exe-
cution of the putchar() function, and the next successful completion of a call to the fflush() or
fclose() function on the same stream, or a call to the exit() or abort() function.
NOTES
The putchar( ) function might be a macro (depending on the compile-time definitions used in the
source). Consequently, you cannot use this interface where a function is necessary; for example,
a subroutine pointer cannot point to it.
When a function is necessary, use the fputc() function instead.
RETURN VALUES
The putchar( ) function and macro, upon successful completion, returns the value written. If this
function or macro fails, it returns the constant EOF. The function sets errno when an error is
encountered.
ERRORS
The putchar( ) function fails if:
• The stream is not open for writing.
• The output file size cannot be increased.
• The stream is unbuffered.
• The stream’s buffer needed to be flushed and the function call caused an underlying
write() or lseek() to be invoked and this underlying operation fails.
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