3 files changed, 25 insertions, 9 deletions
diff --git a/share/qbs/modules/cpp/gcc.js b/share/qbs/modules/cpp/gcc.js
index 7e8e768b0..25fe06861 100644
--- a/share/qbs/modules/cpp/gcc.js
+++ b/share/qbs/modules/cpp/gcc.js
@@ -695,6 +695,22 @@ function standardFallbackValueOrDefault(toolchain, compilerVersion, languageVers
                 {"name": "gcc", "version": "4.7"}
             ]
         },
+        "c17": {
+            "fallback": "c11",
+            "toolchains": [
+                {"name": "xcode", "version": "10.2"},
+                {"name": "clang", "version": "7.0"},
+                {"name": "gcc", "version": "8.1"}
+            ]
+        },
+        "c2x": {
+            "fallback": "c17",
+            "toolchains": [
+                {"name": "xcode", "version": "11.4"},
+                {"name": "clang", "version": "9.0"},
+                {"name": "gcc", "version": "9.0"}
+            ]
+        },
         "c++14": {
             "fallback": "c++1y",
             "toolchains": [
@@ -714,7 +730,7 @@ function standardFallbackValueOrDefault(toolchain, compilerVersion, languageVers
         "c++20": {
             "fallback": "c++2a",
             "toolchains": [
-                {"name": "xcode"}, // ??
+                {"name": "xcode", "version": "12.5"},
                 {"name": "clang", "version": "11.0"},
                 {"name": "gcc", "version": "10.1"}
             ]
@@ -884,7 +900,7 @@ function compilerFlags(project, product, input, output, explicitlyDependsOn) {
         switch (tag) {
         case "c":
         case "objc":
-            var knownValues = ["c11", "c99", "c90", "c89"];
+            var knownValues = ["c2x", "c17", "c11", "c99", "c90", "c89"];
             return Cpp.languageVersion(input.cpp.cLanguageVersion, knownValues, "C");
         case "cpp":
         case "objcpp":
diff --git a/share/qbs/modules/cpp/iar.js b/share/qbs/modules/cpp/iar.js
index 5f56b79f6..632f9af17 100644
--- a/share/qbs/modules/cpp/iar.js
+++ b/share/qbs/modules/cpp/iar.js
@@ -573,7 +573,7 @@ function compilerFlags(project, product, input, outputs, explicitlyDependsOn) {
             args.push("--c89");
             break;
         default:
-            // Default C language version is C11/C99 that
+            // Default C language version is C18/C11/C99 that
             // depends on the IAR version.
             break;
         }
diff --git a/share/qbs/modules/cpp/sdcc.js b/share/qbs/modules/cpp/sdcc.js
index 8b502bd8a..928ded5cf 100644
--- a/share/qbs/modules/cpp/sdcc.js
+++ b/share/qbs/modules/cpp/sdcc.js
@@ -286,18 +286,18 @@ function compilerFlags(project, product, input, outputs, explicitlyDependsOn) {
 
     // C language version flags.
     if (tag === "c") {
-        var knownValues = ["c11", "c99", "c89"];
+        var knownValues = ["c2x", "c17", "c11", "c99", "c89"];
         var cLanguageVersion = Cpp.languageVersion(
                     input.cpp.cLanguageVersion, knownValues, "C");
         switch (cLanguageVersion) {
+        case "c17":
+            cLanguageVersion = "c11";
+            // fall through
         case "c89":
-            args.push("--std-c89");
-            break;
         case "c99":
-            args.push("--std-c99");
-            break;
         case "c11":
-            args.push("--std-c11");
+        case "c2x":
+            args.push("--std-" + cLanguageVersion);
             break;
         }
     }