github ci: also, only execute if binary compiled; some exit code tuning

.github/workflows/ci.yml

@@ -0,0 +1,16 @@
+name: CI
+run-name: continuous integration
+on: [push]
+jobs:
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, ubuntu-22.04, ubuntu-latest]
+        cc: [gcc, clang]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v3
+      - run: ./tests/test.sh
+        shell: bash
+        env:
+          CC: ${{ matrix.cc }}

c

@@ -34,7 +34,7 @@ cleanup() {
 
 # Handle --help, -h, and zero args
 [[ "$1" == "--help" || "$1" == "-h" ]] && { help_msg 1; exit 0; }
-[[ "$#" -lt 1 ]] && { help_msg 2; exit 1; }
+[[ "$#" -lt 1 ]] && { help_msg 2; exit 2; }
 
 # ensure our $CC and $CXX variables are set
 [[ -z "$CC" ]]  && CC=cc
@@ -155,9 +155,14 @@ binname="$tmproot/$id.bin"
 run() {
     trap cleanup SIGINT
 
-    shift
-    (exec -a "$fname" "$binname" "$@")
-    ret=$?
+    if [ -x "$binname" ]; then
+      shift
+      (exec -a "$fname" "$binname" "$@")
+      ret=$?
+    else
+      echo
+      ret=4
+    fi
 
     trap - SIGINT
     cleanup

tests/test.sh

@@ -6,6 +6,11 @@ cd "$(dirname "$BASH_SOURCE")"
 # Load helpers
 source "./test_helpers.sh"
 
+[ -n "$CC" ]  && "$CC"  --version
+[ -n "$CXX" ] && "$CXX" --version
+[ -n "$FC" ]  && "$FC"  --version
+$c --version
+
 # Run tests
 source ./argument_and_link_test/test.sh
 source ./complex_arguments/test.sh