a

libc/vfprint.c

@@ -0,0 +1,34 @@
+#include <u.h>
+#include <libc.h>
+#include "fmtdef.h"
+
+/*
+ * generic routine for flushing a formatting buffer
+ * to a file descriptor
+ */
+int
+_fmtFdFlush(Fmt *f)
+{
+	int n;
+
+	n = (char*)f->to - (char*)f->start;
+	if(n && write((int)f->farg, f->start, n) != n)
+		return 0;
+	f->to = f->start;
+	return 1;
+}
+
+int
+vfprint(int fd, char *fmt, va_list args)
+{
+	Fmt f;
+	char buf[256];
+	int n;
+
+	fmtfdinit(&f, fd, buf, sizeof(buf));
+	f.args = args;
+	n = dofmt(&f, fmt);
+	if(n > 0 && _fmtFdFlush(&f) == 0)
+		return -1;
+	return n;
+}