2.9.5. Dealing with Problems Compiling MySQL

The solution to many problems involves reconfiguring. If you do reconfigure, take note of the following:

If CMake is run after it has previously been run, it may use information that was gathered during its previous invocation. This information is stored in CMakeCache.txt. When CMake starts up, it looks for that file and reads its contents if it exists, on the assumption that the information is still correct. That assumption is invalid when you reconfigure.
Each time you run CMake, you must run make again to recompile. However, you may want to remove old object files from previous builds first because they were compiled using different configuration options.

To prevent old object files or configuration information from being used, run these commands on Unix before re-running CMake:

shell> make cleanshell> rm CMakeCache.txt

Or, on Windows:

shell> devenv MySQL.sln /cleanshell> del CMakeCache.txt

If you build out of the source tree, remove and recreate your build directory before re-running CMake. For instructions on building outside of the source tree, see How to Build MySQL Server with CMake.

On some systems, warnings may occur due to differences in system include files. The following list describes other problems that have been found to occur most often when compiling MySQL:

To define flags to be used by your C or C++ compilers, specify them using the CFLAGS and CXXFLAGS environment variables. You can also specify the compiler names this way using CC and CXX. For example:
```
shell> CC=gccshell> CFLAGS=-O3shell> CXX=g++shell> CXXFLAGS=-O3shell> export CC CFLAGS CXX CXXFLAGS
```
To see what flags you might need to specify, invoke mysql_config with the --cflags and --cxxflags options.
If compilation fails, check whether the MYSQL_MAINTAINER_MODE option is enabled. This mode causes compiler warnings to become errors, so disabling it may enable compilation to proceed.
If your compile fails with errors such as any of the following, you must upgrade your version of make to GNU make:
```
make: Fatal error in reader: Makefile, line 18:Badly formed macro assignment
```
Or:
```
make: file `Makefile' line 18: Must be a separator (:
```
Or:
```
pthread.h: No such file or directory
```
Solaris and FreeBSD are known to have troublesome make programs.

GNU make 3.75 is known to work.
The sql_yacc.cc file is generated from sql_yacc.yy. Normally, the build process does not need to create sql_yacc.cc because MySQL comes with a pregenerated copy. However, if you do need to re-create it, you might encounter this error:
```
"sql_yacc.yy", line xxx fatal: default action causes potential...
```
This is a sign that your version of yacc is deficient. You probably need to install bison (the GNU version of yacc) and use that instead.

Versions of bison older than 1.75 may report this error:
```
sql_yacc.yy:#####: fatal error: maximum table size (32767) exceeded
```
The maximum table size is not actually exceeded; the error is caused by bugs in older versions of bison.

For information about acquiring or updating tools, see the system requirements in Section 2.9, "Installing MySQL from Source".