1 files changed, 43 insertions, 0 deletions
diff --git a/src/stdio/vfscanf.c b/src/stdio/vfscanf.c
new file mode 100644
index 00000000..69f45081
--- /dev/null
+++ b/src/stdio/vfscanf.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+
+#include "stdio_impl.h"
+#include "__scanf.h"
+
+static void f_read(rctx_t *r)
+{
+	FILE *f = r->opaque;
+	if ((r->c = __uflow(f)) >= 0) r->l++;
+}
+
+int vfscanf(FILE *f, const char *fmt, va_list ap)
+{
+	size_t l = strlen(fmt), i, result;
+	rctx_t r = { f_read, (void *)f, 0, isspace };
+	wchar_t fmt2[l+1];
+
+	if (l > 0x100000) {
+		errno = ENOMEM;
+		return -1;
+	}
+	for (i=0; i<=l; i++) fmt2[i] = (unsigned char)fmt[i];
+
+	FLOCK(f);
+
+	result = __scanf(&r, fmt2, ap);
+
+	if (r.u && r.c >= 0) {
+		/* This code takes care of the case where the caller performs
+		 * a nonmatching scanf to leave a character in the unscan
+		 * buffer, followed by an unget, followed by a scanf that
+		 * matches zero characters. In this case the final 'unread'
+		 * character must be returned to the unget buffer rather than
+		 * the unscan buffer. */
+		 f->rpos--;
+	}
+
+	FUNLOCK(f);
+	return result;
+}