Work towards improving signals and processes

examples/sleep.c

@@ -0,0 +1,61 @@
+#if 0
+/*─────────────────────────────────────────────────────────────────╗
+│ To the extent possible under law, Justine Tunney has waived      │
+│ all copyright and related or neighboring rights to this file,    │
+│ as it is written in the following disclaimers:                   │
+│   • http://unlicense.org/                                        │
+│   • http://creativecommons.org/publicdomain/zero/1.0/            │
+╚─────────────────────────────────────────────────────────────────*/
+#endif
+#include "libc/calls/calls.h"
+#include "libc/runtime/runtime.h"
+#include "libc/stdio/stdio.h"
+#include "libc/str/str.h"
+#include "libc/time/time.h"
+#include "libc/x/x.h"
+
+/**
+ * 16kb sleep executable that runs on all operating systems.
+ * https://justine.lol/cosmopolitan/demos/sleep.c
+ * https://justine.lol/cosmopolitan/demos/sleep.com
+ * https://justine.lol/cosmopolitan/index.html
+ */
+
+#define WRITE(s) write(2, s, strlen(s))
+
+int main(int argc, char *argv[]) {
+  char *p;
+  long double x, y;
+  if (argc != 2) {
+    WRITE("Usage: ");
+    WRITE(argv[0]);
+    WRITE(" SECONDS\n");
+    exit(1);
+  }
+  x = 0;
+  for (p = argv[1]; isdigit(*p); ++p) {
+    x *= 10;
+    x += *p - '0';
+  }
+  if (*p == '.') {
+    y = 1;
+    for (++p; isdigit(*p); ++p) {
+      x += (*p - '0') * (y /= 10);
+    }
+  }
+  switch (*p) {
+    case 'm':
+      x *= 60;
+      break;
+    case 'h':
+      x *= 60 * 60;
+      break;
+    case 'd':
+      x *= 60 * 60 * 24;
+      break;
+    default:
+      break;
+  }
+  dsleep(x);
+  return 0;
+}