diff --git a/include/libssh2.h b/include/libssh2.h
index 8caa90cb..1b0d6905 100644
--- a/include/libssh2.h
+++ b/include/libssh2.h
@@ -521,8 +521,9 @@ LIBSSH2_API int libssh2_userauth_password_ex(LIBSSH2_SESSION *session,
                                              LIBSSH2_PASSWD_CHANGEREQ_FUNC((*passwd_change_cb)));
 
 #define libssh2_userauth_password(session, username, password) \
- libssh2_userauth_password_ex((session), (username), strlen(username), \
-                              (password), strlen(password), NULL)
+ libssh2_userauth_password_ex((session), (username),           \
+                              (unsigned int)strlen(username),  \
+                              (password), (unsigned int)strlen(password), NULL)
 
 LIBSSH2_API int
 libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session,
@@ -534,9 +535,10 @@ libssh2_userauth_publickey_fromfile_ex(LIBSSH2_SESSION *session,
 
 #define libssh2_userauth_publickey_fromfile(session, username, publickey, \
                                             privatekey, passphrase)     \
-  libssh2_userauth_publickey_fromfile_ex((session), (username), \
-                                         strlen(username), (publickey), \
-                                         (privatekey), (passphrase))
+    libssh2_userauth_publickey_fromfile_ex((session), (username),       \
+                                           (unsigned int)strlen(username), \
+                                           (publickey),                 \
+                                           (privatekey), (passphrase))
 
 LIBSSH2_API int
 libssh2_userauth_publickey(LIBSSH2_SESSION *session,
@@ -561,10 +563,13 @@ libssh2_userauth_hostbased_fromfile_ex(LIBSSH2_SESSION *session,
 #define libssh2_userauth_hostbased_fromfile(session, username, publickey, \
                                             privatekey, passphrase, hostname) \
  libssh2_userauth_hostbased_fromfile_ex((session), (username), \
-                                        strlen(username), (publickey), \
-                                        (privatekey), (passphrase), \
-                                        (hostname), strlen(hostname), \
-                                        (username), strlen(username))
+                                        (unsigned int)strlen(username), \
+                                        (publickey),                    \
+                                        (privatekey), (passphrase),     \
+                                        (hostname),                     \
+                                        (unsigned int)strlen(hostname), \
+                                        (username),                     \
+                                        (unsigned int)strlen(username))
 
 /*
  * response_callback is provided with filled by library prompts array,
@@ -578,10 +583,11 @@ libssh2_userauth_keyboard_interactive_ex(LIBSSH2_SESSION* session,
                                          unsigned int username_len,
                                          LIBSSH2_USERAUTH_KBDINT_RESPONSE_FUNC((*response_callback)));
 
-#define libssh2_userauth_keyboard_interactive(session, username, \
-                                              response_callback) \
- libssh2_userauth_keyboard_interactive_ex((session), (username), \
-                                          strlen(username), (response_callback))
+#define libssh2_userauth_keyboard_interactive(session, username,        \
+                                              response_callback)        \
+    libssh2_userauth_keyboard_interactive_ex((session), (username),     \
+                                             (unsigned int)strlen(username), \
+                                             (response_callback))
 
 LIBSSH2_API int libssh2_poll(LIBSSH2_POLLFD *fds, unsigned int nfds,
                              long timeout);
@@ -635,9 +641,10 @@ LIBSSH2_API int libssh2_channel_setenv_ex(LIBSSH2_CHANNEL *channel,
                                           const char *value,
                                           unsigned int value_len);
 
-#define libssh2_channel_setenv(channel, varname, value) \
- libssh2_channel_setenv_ex((channel), (varname), strlen(varname), (value), \
-                           strlen(value))
+#define libssh2_channel_setenv(channel, varname, value)                 \
+    libssh2_channel_setenv_ex((channel), (varname),                     \
+                              (unsigned int)strlen(varname), (value),   \
+                              (unsigned int)strlen(value))
 
 LIBSSH2_API int libssh2_channel_request_pty_ex(LIBSSH2_CHANNEL *channel,
                                                const char *term,
@@ -646,10 +653,12 @@ LIBSSH2_API int libssh2_channel_request_pty_ex(LIBSSH2_CHANNEL *channel,
                                                unsigned int modes_len,
                                                int width, int height,
                                                int width_px, int height_px);
-#define libssh2_channel_request_pty(channel, term) \
- libssh2_channel_request_pty_ex((channel), (term), strlen(term), NULL, 0, \
-                                LIBSSH2_TERM_WIDTH, LIBSSH2_TERM_HEIGHT, \
-                                LIBSSH2_TERM_WIDTH_PX, LIBSSH2_TERM_HEIGHT_PX)
+#define libssh2_channel_request_pty(channel, term)                      \
+    libssh2_channel_request_pty_ex((channel), (term),                   \
+                                   (unsigned int)strlen(term),          \
+                                   NULL, 0,                             \
+                                   LIBSSH2_TERM_WIDTH, LIBSSH2_TERM_HEIGHT, \
+                                   LIBSSH2_TERM_WIDTH_PX, LIBSSH2_TERM_HEIGHT_PX)
 
 LIBSSH2_API int libssh2_channel_request_pty_size_ex(LIBSSH2_CHANNEL *channel,
                                                     int width, int height,
@@ -676,11 +685,11 @@ LIBSSH2_API int libssh2_channel_process_startup(LIBSSH2_CHANNEL *channel,
                                   NULL, 0)
 #define libssh2_channel_exec(channel, command) \
   libssh2_channel_process_startup((channel), "exec", sizeof("exec") - 1, \
-                                  (command), strlen(command))
+                                  (command), (unsigned int)strlen(command))
 #define libssh2_channel_subsystem(channel, subsystem) \
   libssh2_channel_process_startup((channel), "subsystem",              \
                                   sizeof("subsystem") - 1, (subsystem), \
-                                  strlen(subsystem))
+                                  (unsigned int)strlen(subsystem))
 
 LIBSSH2_API ssize_t libssh2_channel_read_ex(LIBSSH2_CHANNEL *channel,
                                             int stream_id, char *buf,