misc: Add `vformat_len()`

This works exactly like `format_len()`, except that it uses `va_list`
rather than variadic arguments.

1 files changed, 4 insertions, 0 deletions

diff --git a/misc.c b/misc.c
index 4c0cab0..6e10a57 100644
--- a/misc.c
+++ b/misc.c
@@ -201,6 +201,10 @@ char *skip_whitespace(const char *str) {
 	}
 }
 
+int vformat_len(const char *fmt, va_list args) {
+	return vsnprintf(NULL, 0, fmt, args);
+}
+
 int format_len(const char *fmt, ...) {
 	int len = 0;
 	va_list args;