CGContextRef myContext = [[NSGraphicsContext currentContext] graphicsPort];

error: invalid conversion from 'void*' to 'CGContext*'

CGContextRef myContext = static_cast<CGContextRef>([[NSGraphicsContext currentContext] graphicsPort]);

cristi:tmp diciu$ cat test.c
int main()
{
    char * t = "test";
    void * m = t;
    char * g;

    g=m;

}

cristi:tmp diciu$ g++ test.c
test.c: In function ‘int main()’:
test.c:7: error: invalid conversion from ‘void*’ to ‘char*’

cristi:tmp diciu$ gcc test.c