1 files changed, 33 insertions, 0 deletions
diff --git a/getul_n.c b/getul_n.c
new file mode 100644
index 0000000..cf150c9
--- /dev/null
+++ b/getul_n.c
@@ -0,0 +1,33 @@
+#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_n(const char *const s, unsigned long *const out)
+{
+    char *end;
+    unsigned long v;
+
+    errno = 0;
+    v = strtoull(s, &end, 10);
+
+    if (errno)
+    {
+        fprintf(stderr, "%s: strtoul(3) %s: %s\n", __func__, s,
+            strerror(errno));
+        return -1;
+    }
+    else if (*end || v > LONG_MAX)
+    {
+        fprintf(stderr, "%s: invalid number: %.*s\n", __func__,
+            (int)(end - s), s);
+        return -1;
+    }
+
+    *out = v;
+    return 0;
+}