1 files changed, 46 insertions, 0 deletions
diff --git a/compat/vasprintf.c b/compat/vasprintf.c
new file mode 100644
index 0000000..d76f3ef
--- /dev/null
+++ b/compat/vasprintf.c
@@ -0,0 +1,46 @@
+/* from mandoc, with tweaks */
+/*
+ * Copyright (c) 2015 Ingo Schwarze <schwarze@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * This fallback implementation is not efficient:
+ * It does the formatting twice.
+ * Short of fiddling with the unknown internals of the system's
+ * printf(3) or completely reimplementing printf(3), i can't think
+ * of another portable solution.
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int
+vasprintf(char **ret, const char *format, va_list ap)
+{
+	char	 buf[2];
+	va_list	 ap2;
+	int	 sz;
+
+	va_copy(ap2, ap);
+	sz = vsnprintf(buf, sizeof(buf), format, ap2);
+	va_end(ap2);
+
+	if (sz != -1 && (*ret = malloc(sz + 1)) != NULL) {
+		if (vsnprintf(*ret, sz + 1, format, ap) == sz)
+			return sz;
+		free(*ret);
+	}
+	*ret = NULL;
+	return -1;
+}