How should I handle "cast from ‘void*’ to ‘int’ loses precision" when compiling 32-bit code on 64-bit machine?

c++ linux portability 32bit-64bit
badkya picture badkya · Jan 8, 2010 · Viewed 49k times · Source

I have a package that compiles and works fine on a 32-bit machine. I am now trying to get it to compile on a 64-bit machine and find the following error-

 error: cast from ‘void*’ to ‘int’ loses precision

Is there a compiler flag to suppress these errors? or do I have to manually edit these files to avoid these casts?

Answer

Reed Copsey picture Reed Copsey · Jan 8, 2010

The issue is that, in 32bits, an int (which is a 32bit integer) will hold a pointer value.

When you move to 64bit, you can no longer store a pointer in an int - it isn't large enough to hold a 64bit pointer. The intptr_t type is designed for this.

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