diff --git a/Action.c b/Action.c
index c4d71479..6d7782ca 100644
--- a/Action.c
+++ b/Action.c
@@ -107,7 +107,7 @@ bool Action_setUserOnly(const char* userName, uid_t* userId) {
       *userId = user->pw_uid;
       return true;
    }
-   *userId = -1;
+   *userId = (uid_t)-1;
    return false;
 }
 
diff --git a/TraceScreen.c b/TraceScreen.c
index 8e5f61e7..2956b569 100644
--- a/TraceScreen.c
+++ b/TraceScreen.c
@@ -109,13 +109,13 @@ void TraceScreen_updateTrace(InfoScreen* super) {
    struct timeval tv;
    tv.tv_sec = 0; tv.tv_usec = 500;
    int ready = select(this->fd_strace+1, &fds, NULL, NULL, &tv);
-   int nread = 0;
+   size_t nread = 0;
    if (ready > 0 && FD_ISSET(this->fd_strace, &fds))
       nread = fread(buffer, 1, sizeof(buffer) - 1, this->strace);
    if (nread && this->tracing) {
-      char* line = buffer;
+      const char* line = buffer;
       buffer[nread] = '\0';
-      for (int i = 0; i < nread; i++) {
+      for (size_t i = 0; i < nread; i++) {
          if (buffer[i] == '\n') {
             buffer[i] = '\0';
             if (this->contLine) {
diff --git a/htop.c b/htop.c
index 44182ae1..8c813564 100644
--- a/htop.c
+++ b/htop.c
@@ -74,7 +74,7 @@ static CommandLineSettings parseArguments(int argc, char** argv) {
    CommandLineSettings flags = {
       .pidMatchList = NULL,
       .commFilter = NULL,
-      .userId = -1, // -1 is guaranteed to be an invalid uid_t (see setreuid(2))
+      .userId = (uid_t)-1, // -1 is guaranteed to be an invalid uid_t (see setreuid(2))
       .sortKey = 0,
       .delay = -1,
       .useColors = true,