_CP_field is equivalent to the result = field(string1, string2, expression) BASIC statement.
int _CP_field(CPSTR** result, CPSTR* string1, CPSTR* string2, int expression)
This function returns -1 if an error occurs. The error code is contained in _CP_errno.
/* Prints "ab 2 5" */
CPSTR * s = _CP_mkstr("zdabdz");
CPSTR * t = _CP_mkstr("d");
int i,j;
_CP_field(&s,s,t,2);
_CP_col1(&i);
_CP_col2(&j);
_CP_TERM(s);
_CP_unix_env();
printf("%s %d %d\n",_CP_SADDR(s),i,j);