旧包中的C / C ++静态字符串

Question

I have an old C/C++ package which I am trying to compile with CygWin because it needs Motif and other X- things. Most of it compiles OK but there are some warnings due to lines like....

static String fallbackResources[] = { "Joe", ..etc.. , NULL};

I get the compiler warning: deprecated conversion from string constant to 'String {aka char*}'

I have googled and found many suggestions to avoid this warning by changing occurrences of say "char* fred[]" to "const char* fred[]" which I have done for most of the c++ files in the package and this has worked perfectly to remove the compiler warnings.

However I am stuck with the "static String" lines since when I change them by inserting "const" before "String" it makes no difference and if I change the "String" to "const char*" the warning disappears but the program doesn't compile due to an error later on where it sends the array to another function....

cannot convert 'const char*' to 'char**' for argument '7' to....

Any help would be very much appreciated.

Answer 1

Thanks all, googled more and found ( https://stackoverflow.com/a/14648630/3100869 ) - the answer seems to be to use const_cast's like this:

static String fallbackResources[] = { const_cast( "Joe" ) , ..etc.. , NULL};

... and the warnings go away!

Answer 2

The problem is that you've got two levels of const on pointers: the pointer itself and what it points to. char const * is a pointer to const char (read from right to left), whereas char* const is a const pointer to char.

It seems that String in your case is a typedef for char* . Making that const like you did turns it into a char* const . You need to fix the typedef.