I am trying to create a string from two strings using the following code and getting the following code and getting the warning

In file included from ./prgms/raytrac.cc:62:0:
baselib/clorfncs.hh: In function ‘void pr_hmisc(FILE*, int)’:
baselib/clorfncs.hh:494:21: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]

  char*  vbMsg01a = "important message. Each level can assume that all";
  const char*  vbMsg01b = " lower levels are also printing";
  strcat(vbMsg01a,vbMsg01b);
  const char*  vbMsg01c;
  strcpy (vbMsg01c,vbMsg01a);

strcpy takes arguments in order char*, const char*, as does strcat.

Hence your code should be something like this:

const char*  vbMsg01d = vbMsg01a;
char* vbMsg01e; 
strcpy(vbMsg01e,vbMsg01d);
const char*  vbMsg01c = vbMsg01e;

Have you allocated memory for vbMsg01c before trying to store characters in it...