Fix $fscanf etc to return -1 on EOF (#3113).

Changes

@@ -20,6 +20,7 @@ Verilator 4.219 devel
 * Fix skipping public enum values with four-state values (#3303).
 * Fix $readmem file not found to be warning not error (#3310). [Alexander Grobman]
 * Fix class stringification on wide arrays (#3312). [Iru Cai]
+* Fix $fscanf etc to return -1 on EOF (#3113). [Jose Tejada]
 * Fix public function arguments that are arrayed (#3316). [pawel256]
 * Fix unnamedblk error on foreach (#3321). [Aliaksei Chapyzhenka]
 * Fix crash in recursive module inlining (#3324). [Larry Doolittle]

include/verilated.cpp

@@ -1497,7 +1497,7 @@ void VL_FWRITEF(IData fpi, const char* formatp, ...) VL_MT_SAFE {
 IData VL_FSCANF_IX(IData fpi, const char* formatp, ...) VL_MT_SAFE {
     // While threadsafe, each thread can only access different file handles
     FILE* const fp = VL_CVT_I_FP(fpi);
-    if (VL_UNLIKELY(!fp)) return 0;
+    if (VL_UNLIKELY(!fp)) return ~0U;  // -1
 
     va_list ap;
     va_start(ap, formatp);

include/verilated_imp.h

@@ -316,14 +316,14 @@ public:  // But only for verilated*.cpp
     IData fdSeek(IData fdi, IData offset, IData origin) VL_MT_SAFE_EXCLUDES(m_fdMutex) {
         const VerilatedLockGuard lock{m_fdMutex};
         const VerilatedFpList fdlist = fdToFpList(fdi);
-        if (VL_UNLIKELY(fdlist.size() != 1)) return 0;
+        if (VL_UNLIKELY(fdlist.size() != 1)) return ~0U;  // -1
         return static_cast<IData>(
             std::fseek(*fdlist.begin(), static_cast<long>(offset), static_cast<int>(origin)));
     }
     IData fdTell(IData fdi) VL_MT_SAFE_EXCLUDES(m_fdMutex) {
         const VerilatedLockGuard lock{m_fdMutex};
         const VerilatedFpList fdlist = fdToFpList(fdi);
-        if (VL_UNLIKELY(fdlist.size() != 1)) return 0;
+        if (VL_UNLIKELY(fdlist.size() != 1)) return ~0U;  // -1
         return static_cast<IData>(std::ftell(*fdlist.begin()));
     }
     void fdWrite(IData fdi, const std::string& output) VL_MT_SAFE_EXCLUDES(m_fdMutex) {

test_regress/t/t_sys_file_basic.pl

@@ -13,7 +13,6 @@ scenarios(simulator => 1);
 unlink("$Self->{obj_dir}/t_sys_file_basic_test.log");
 
 compile(
-    v_flags2 => ['+incdir+../include'],
     # Build without cached objects, see bug363
     make_flags => 'VM_PARALLEL_BUILDS=0',
     );

test_regress/t/t_sys_file_eof.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_sys_file_eof.v

@@ -0,0 +1,34 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+`include "verilated.v"
+
+`define checkd(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%0d exp=%0d\n", `__FILE__,`__LINE__, (gotv), (expv)); $stop; end while(0);
+
+module t;
+
+   integer f;
+   integer i;
+   integer j;
+
+   initial begin
+      f = $fopen("/does-not-exist", "r");
+      `checkd(f, 0);
+      i = $fscanf(f, "check %d", j);
+      `checkd(i, -1);
+      i = $fgetc(f);
+      `checkd(i, -1);
+      i = $ftell(f);
+      `checkd(i, -1);
+      i = $rewind(f);
+      `checkd(i, -1);
+      i = $fseek(f, 0, 0);
+      `checkd(i, -1);
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule