Fix UB (signed char passed to <cctype> function)

Passing char to a <cctype> function is UB for characters that are outside the range [0...255, EOF].

You have to cast chars to uchar so the implicit conversion to int
does not produce negative values.

Amends a6ffce09ce6d4fd39fbb50eb58f7b5d1027f4d60.

Change-Id: I597ee3ff87d38c40dbdf794ee07d302da26f520e
Reviewed-by: Mike Krus <mike.krus@kdab.com>
(cherry picked from commit cf084d958c1d795fbdc06b6a377ab61d68e0960a)
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/render/shadergraph/qshadergenerator.cpp b/src/render/shadergraph/qshadergenerator.cpp
index 05e578c78..7ca29b03b 100644
--- a/src/render/shadergraph/qshadergenerator.cpp
+++ b/src/render/shadergraph/qshadergenerator.cpp
@@ -616,7 +616,7 @@ QByteArray QShaderGenerator::createShaderCode(const QStringList &enabledLayers)
             int end = begin + 1;
             char endChar = line.at(end);
             const int size = line.size();
-            while (end < size && (std::isalnum(endChar) || endChar == '_')) {
+            while (end < size && (std::isalnum(uchar(endChar)) || endChar == '_')) {
                 ++end;
                 endChar = line.at(end);
             }