diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d965ef8..83696c5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -89,7 +89,7 @@ jobs:
         run: sudo apt-get --yes install cppcheck
       - name: cppcheck source code
         # TODO: don't suppress "src/printf.c"
-        run: cppcheck --quiet --error-exitcode=1 --std=c99 --enable=warning,style,performance,portability --suppress='*:src/printf.c' include/ src/ libc/
+        run: cppcheck --quiet --error-exitcode=1 --std=c99 --enable=warning,style,performance,portability --suppress='*:src/printf.c' include/ src/ libc/ libm/
       - name: cppcheck examples
         run: cppcheck --quiet --error-exitcode=1 --std=c99 --enable=warning,style,performance,portability --suppress=duplicateExpression --suppress=staticStringCompare examples/
       - name: cppcheck tests