Build failure with ODBC support due to PREFIX macro conflict between unixODBC and NumberFormatter.h

[Hasoo]

Environment

• OS: Rocky Linux 9.6 (Blue Onyx)
• GCC: 11.5.0 20240719 (Red Hat 11.5.0-5)
• unixODBC: 2.3.9-4.el9.x86_64
• unixODBC-devel: 2.3.9-4.el9.x86_64
• Poco version: 1.14.2-release

Problem Description

When building Poco library with ODBC support on Rocky Linux 9, compilation fails due to a macro name conflict between unixODBC and Poco's NumberFormatter.h.

Error Details

curl -LO https://github.com/pocoproject/poco/archive/refs/tags/poco-1.14.2-release.tar.gz &&
tar xzvf poco-1.14.2-release.tar.gz &&
cd poco-poco-1.14.2-release &&
./configure --omit=Data/MySQL,Data/PostgreSQL,Data/SQLite --no-tests --no-samples --prefix=$HOME/workspace/packages/poco --odbc-lib=/usr/lib64 --odbc-include=/usr/include &&
make -j$(nproc) &&
make install

The compilation fails with the following error:

poco-poco-1.14.2-release/Foundation/include/Poco/NumberFormatter.h:51:17: error: expected identifier before string constant
 51 |                 PREFIX = 1 << 0,
    |                 ^~~~~~

Root Cause

The issue occurs because:

1. unixodbc_conf-x86_64.h defines PREFIX as a macro: #define PREFIX "/usr"
2. Poco's NumberFormatter.h uses PREFIX as an enum value
3. This creates a conflict when ODBC headers are included

Workaround

The issue can be resolved by adding #undef PREFIX after including ODBC headers in Data/ODBC/include/Poco/Data/ODBC/Unicode.h:

#include <sqlext.h>
#include <sqltypes.h>
#include <sqlucode.h>
#ifdef PREFIX
#undef PREFIX
#endif

Suggested Fix

Consider adding the #undef PREFIX directive to prevent this macro conflict, or use a more specific name for the enum value in NumberFormatter.h to avoid potential conflicts with system headers.

[matejk]

Thank you for the report. Does this problem also occur when building with CMake?

[Hasoo]

Thank you for the report. Does this problem also occur when building with CMake?

Yes, I tested with CMake and encountered the same issue. The problem occurs with both build systems (GNU Make and CMake)

curl -LO https://github.com/pocoproject/poco/archive/refs/tags/poco-1.14.2-release.tar.gz &&       
  tar xzvf poco-1.14.2-release.tar.gz &&       
  cd poco-poco-1.14.2-release &&       
  mkdir -p $HOME/workspace/packages/poco &&                                                                                                                                       
  cmake -B build \                                                                                                                                                                
    -DCMAKE_INSTALL_PREFIX=$HOME/workspace/packages/poco \                                                                                                                        
    -DENABLE_DATA_MYSQL=OFF \                                                                                                                                                     
    -DENABLE_DATA_POSTGRESQL=OFF \                                                                                                                                                
    -DENABLE_DATA_SQLITE=OFF \                                                                                                                                                    
    -DENABLE_TESTS=OFF \                                                                                                                                                          
    -DENABLE_SAMPLES=OFF \                                                                                                                                                        
    -DCMAKE_BUILD_TYPE=Release &&                                                                                                                                                  
  cmake --build build -j$(nproc) &&                                                                                                                                                     
  cmake --install build

[matejk]

Added HEX_ prefix to hex formatting options to avoid conflicts with other libraries.