Missing includes in ModbusServerPort_p.h causes build failure with bcc64x compiler

[bravo-jcd]

Missing includes in ModbusServerPort_p.h causes build failure with bcc64x compiler

Environment

• ModbusLib Version: 0.4.6
• Compiler: Embarcadero bcc64x (Clang 20.1.7 based) - RAD Studio 37.0
• Platform: Windows 64-bit
• Build System: CMake 4.1.1 with Ninja

Description

Building ModbusLib 0.4.6 with the Embarcadero bcc64x compiler fails due to missing header includes in src/ModbusServerPort_p.h. The file uses malloc, free, and memcpy functions without including the required standard library headers.

Error Output

[6/27] Building CXX object src/CMakeFiles/modbus.dir/ModbusServerPort.cpp.o
FAILED: src/CMakeFiles/modbus.dir/ModbusServerPort.cpp.o
In file included from J:/Projects/BravoSystems/SVN/3rdparty/ModBusLib/ModbusLib-0.4.6/src/ModbusServerPort.cpp:24:
Error E5199 J:/Projects/BravoSystems/SVN/3rdparty/ModBusLib/ModbusLib-0.4.6/src\ModbusServerPort_p.h 50(13): use of undeclared identifier 'free'
   50 |             free(settings.unitmap);
      |             ^
Error E5199 J:/Projects/BravoSystems/SVN/3rdparty/ModBusLib/ModbusLib-0.4.6/src\ModbusServerPort_p.h 63(13): use of undeclared identifier 'free'
   63 |             free(settings.unitmap);
      |             ^
Error E5200 J:/Projects/BravoSystems/SVN/3rdparty/ModBusLib/ModbusLib-0.4.6/src\ModbusServerPort_p.h 66(59): use of undeclared identifier 'malloc'; did you mean '_alloca'?
   66 |             settings.unitmap = reinterpret_cast<uint8_t*>(malloc(MB_UNITMAP_SIZE));
      |                                                           ^~~~~~
      |                                                           _alloca

Similar errors occur in:

• ModbusServerResource.cpp
• ModbusTcpServer.cpp
• win/ModbusTcpServer_win.cpp

Root Cause

The file src/ModbusServerPort_p.h uses the following standard C functions without including their headers:

• malloc and free (line 50, 63, 66) - require <cstdlib> or <stdlib.h>
• memcpy (line 67) - requires <cstring> or <string.h>

While GCC and some other compilers may include these headers transitively, the bcc64x compiler requires explicit includes.

Proposed Fix

Add the missing includes at the top of src/ModbusServerPort_p.h:

#ifndef MODBUSSERVERPORT_P_H
#define MODBUSSERVERPORT_P_H

#include <cstdlib>  // for malloc, free
#include <cstring>  // for memcpy
#include "ModbusObject_p.h"

Testing

After applying this fix, ModbusLib 0.4.6 builds successfully with bcc64x:

• Static library build completes without errors
• All 27/27 build targets succeed
• Library file generated: libmodbus.a

Impact

This issue affects any build environment using compilers with stricter header inclusion requirements. The fix is minimal, follows C++ best practices (explicit includes), and has no negative impact on other compilers.

Additional Information

• This issue does not affect GCC or standard Clang builds due to transitive header inclusion
• The fix follows standard C++ practices of explicitly including headers for used functions
• No changes to functionality, only header includes

fix-missing-includes.patch