1 files changed, 52 insertions, 0 deletions
diff --git a/getul.c b/getul.c
new file mode 100644
index 0000000..57fc394
--- /dev/null
+++ b/getul.c
@@ -0,0 +1,52 @@
+/*
+ * nanobbs, a tiny forums software.
+ * Copyright (C) 2025-2026  Xavier Del Campo Romero
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#define _POSIX_C_SOURCE 200809L
+
+#include "utils.h"
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+int getul(const char **const s, unsigned long *const out)
+{
+    char *end;
+    unsigned long v;
+
+    errno = 0;
+    v = strtoul(*s, &end, 10);
+
+    if (errno)
+    {
+        fprintf(stderr, "%s: strtoul(3) %s: %s\n", __func__, *s,
+            strerror(errno));
+        return -1;
+    }
+    else if ((*end != '/' && *end) || v > LONG_MAX || !v)
+    {
+        fprintf(stderr, "%s: invalid number: %.*s\n", __func__,
+            (int)(end - *s), *s);
+        return -1;
+    }
+
+    *out = v;
+    *s = *end ? end + 1 : end;
+    return 0;
+}