From e55338f9277192d2ec9bad13571d7758e2854f91 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 5 Apr 2020 10:11:28 -0400
Subject: [PATCH] Support $fflush without arguments, #1638.

---
 Changes                           | 2 ++
 include/verilated.cpp             | 4 ++++
 src/V3EmitC.cpp                   | 2 +-
 src/verilog.y                     | 2 +-
 test_regress/t/t_sys_file_basic.v | 2 ++
 5 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/Changes b/Changes
index 938de3927..0c5e94bfc 100644
--- a/Changes
+++ b/Changes
@@ -7,6 +7,8 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 **    Add simplistic class support with many restrictions, see manual, #377.
 
+****  Support $fflush without arguments, #1638.
+
 
 * Verilator 4.032 2020-04-04
 
diff --git a/include/verilated.cpp b/include/verilated.cpp
index efdb84aff..adc6abacb 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -1181,6 +1181,10 @@ void VL_FCLOSE_I(IData fdi) VL_MT_SAFE {
     VerilatedImp::fdDelete(fdi);
 }
 
+void VL_FFLUSH_ALL() VL_MT_SAFE {
+    fflush(stdout);
+}
+
 void VL_SFORMAT_X(int obits, CData& destr, const char* formatp, ...) VL_MT_SAFE {
     static VL_THREAD_LOCAL std::string output;  // static only for speed
     output = "";
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index 8d0a85f66..6502f8bb4 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -557,7 +557,7 @@ public:
     }
     virtual void visit(AstFFlush* nodep) VL_OVERRIDE {
         if (!nodep->filep()) {
-            puts("fflush(stdout);\n");
+            puts("Verilated::flushCall();\n");
         } else {
             puts("if (");
             iterateAndNextNull(nodep->filep());
diff --git a/src/verilog.y b/src/verilog.y
index 7fbc7200b..6013f2248 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -3232,7 +3232,7 @@ system_t_call<nodep>:		// IEEE: system_tf_call (as task)
 	|	yD_SYSTEM '(' expr ')'			{ $$ = new AstSystemT($1, $3); }
 	//
 	|	yD_FCLOSE '(' idClassSel ')'		{ $$ = new AstFClose($1, $3); }
-	|	yD_FFLUSH parenE			{ $$ = NULL; BBUNSUP($1, "Unsupported: $fflush of all handles does not map to C++."); }
+	|	yD_FFLUSH parenE			{ $$ = new AstFFlush($1, NULL); }
 	|	yD_FFLUSH '(' expr ')'			{ $$ = new AstFFlush($1, $3); }
 	|	yD_FINISH parenE			{ $$ = new AstFinish($1); }
 	|	yD_FINISH '(' expr ')'			{ $$ = new AstFinish($1); DEL($3); }
diff --git a/test_regress/t/t_sys_file_basic.v b/test_regress/t/t_sys_file_basic.v
index bd431eb33..43cbf3c31 100644
--- a/test_regress/t/t_sys_file_basic.v
+++ b/test_regress/t/t_sys_file_basic.v
@@ -61,6 +61,8 @@ module t;
       $fwriteb(file, "b: "); $fwriteb(file, i); $fwriteb(file, " "); $fdisplayb(file, i);
 
       $fflush(file);
+      $fflush();
+      $fflush;
 
       $fclose(file);
 `ifdef verilator