manual: Move mbstouwcs to an example C file

1 files changed, 28 insertions, 0 deletions

diff --git a/manual/examples/mbstouwcs.c b/manual/examples/mbstouwcs.c
new file mode 100644
index 0000000000..5d223da2ae
--- /dev/null
+++ b/manual/examples/mbstouwcs.c
@@ -0,0 +1,28 @@
+#include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+
+/* Do not include the above headers in the example.
+*/
+wchar_t *
+mbstouwcs (const char *s)
+{
+  size_t len = strlen (s);
+  wchar_t *result = malloc ((len + 1) * sizeof (wchar_t));
+  wchar_t *wcp = result;
+  wchar_t tmp[1];
+  mbstate_t state;
+  size_t nbytes;
+
+  memset (&state, '\0', sizeof (state));
+  while ((nbytes = mbrtowc (tmp, s, len, &state)) > 0)
+    {
+      if (nbytes >= (size_t) -2)
+        /* Invalid input string.  */
+        return NULL;
+      *wcp++ = towupper (tmp[0]);
+      len -= nbytes;
+      s += nbytes;
+    }
+  return result;
+}