error: invalid conversion from ‘const char*’ to ‘char*’

Applications Programming
1

Compiling xpp (The X Printing Panel) on SL6 (RHEL6 essentially):

xpp.cxx: In constructor �printFiles::printFiles(int, char**, int&)�:
xpp.cxx:200: error: invalid conversion from �const char*� to �char*�

The same error with all c++ constructors - gcc 4.4.4.

If anyone can throw any light on this it would be very much appreciated - I'm after getting BitBox[1] up and running and it won't run without xpp.
[1] Free 'Browser in a Box' Runs Firefox 4 with Ultra Security | PCWorld Business Center

2

Casting the expression on the right side of the equals sign should take care of this.

3

Keep in mind that the code might still have to abide by the const-ness even after you typecast it. Typecasting a "string" to char * won't stop the program from crashing when you try to modify it.

4

Not if it's cast from char* to const char* but the other way around...sure!

5

The function prototype:

printFiles::printFiles(int  argc,         /* I - Number of command-line arguments */
                          char *argv[],      /* I - Command-line arguments */
                          int &exitstat);    /* O - != 0 if an error occurred */

I was working on the basis it was probably something to do with the version of gcc in use - however compat libs and gcc3 do not seem to fix it.

6 
xpp.cxx:200: error: invalid conversion from �const char*� to �char*�

Like shamrock says you may need to modify something to fix it. Since you haven't posted line 200 (and a bit of context) we don't know exactly what's making it throw up though.

7

OK, I was thinking the error was in the function prototype, after all that was what was given, however it is further down (rusty!):

              {
              char *tmp; 

              if ((tmp = strchr(dest,'/'))) {
                tmp[0] = '\0';
                instance = tmp + 1;
              }

Specifically the tmp assignment.

The phenomena is explained here by the looks... GCC 4.4 Release Series � Porting to the New Tools

8

tmp=(char *)strchr(...

1 Like
9 
if ((tmp = (char*)strchr(dest,'/'))) {

Seems to have fixed it!

Thanks for your time guys :slight_smile: