putchar[write a character (macro)]

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putchar
[write a character (macro)]

SYNOPSIS
#include <stdio.h>
int putchar(int ch);
int _putchar_r(void *reent, int ch);

DESCRIPTION
putchar is a macro, defined in stdio.h. putchar writes its argument to the standard output stream, after converting it from an int to an unsigned char.

The alternate function, _putchar_r, is a reentrant version. The extra argument, reent, is a pointer to a reentrancy structure.

RETURNS
If successful, putchar returns its argument, ch. If an error intervenes, the result is EOF. You can use ferror(stdin) to query for errors.

COMPLIANCE
ANSI C requires putchar; it suggests, but does not require, that putchar be implemented as a macro.

Supporting OS subroutines required: close, fstat, isatty, lseek, read, sbrk, write.