print.c

著名操作系统Plan 9的第三版的部分核心源代码。现在很难找到了。Plan 9是bell实验室开发的Unix后继者。

#include <u.h>
#include <libc.h>

#define	SIZE	4096
extern	int	printcol;

int
print(char *fmt, ...)
{
	char buf[SIZE], *out;
	va_list arg;
	int n;

	va_start(arg, fmt);
	out = doprint(buf, buf+SIZE, fmt, arg);
	va_end(arg);
	n = write(1, buf, (long)(out-buf));
	return n;
}

int
fprint(int f, char *fmt, ...)
{
	char buf[SIZE], *out;
	va_list arg;
	int n;

	va_start(arg, fmt);
	out = doprint(buf, buf+SIZE, fmt, arg);
	va_end(arg);
	n = write(f, buf, (long)(out-buf));
	return n;
}

int
sprint(char *buf, char *fmt, ...)
{
	char *out;
	va_list arg;
	int scol;

	scol = printcol;
	va_start(arg, fmt);
	out = doprint(buf, buf+SIZE, fmt, arg);
	va_end(arg);
	printcol = scol;
	return out-buf;
}

int
snprint(char *buf, int len, char *fmt, ...)
{
	char *out;
	va_list arg;
	int scol;

	scol = printcol;
	va_start(arg, fmt);
	out = doprint(buf, buf+len, fmt, arg);
	va_end(arg);
	printcol = scol;
	return out-buf;
}

char*
seprint(char *buf, char *e, char *fmt, ...)
{
	char *out;
	va_list arg;
	int scol;

	scol = printcol;
	va_start(arg, fmt);
	out = doprint(buf, e, fmt, arg);
	va_end(arg);
	printcol = scol;
	return out;
}