char *s;
/* to upper */
- for ( s = str; *s; s++ ) {
- *s = TOUPPER( (unsigned char) *s );
+ if ( str ) {
+ for ( s = str; *s; s++ ) {
+ *s = TOUPPER( (unsigned char) *s );
+ }
}
return( str );
char *s;
/* to lower */
- for ( s = str; *s; s++ ) {
- *s = TOLOWER( (unsigned char) *s );
+ if ( str ) {
+ for ( s = str; *s; s++ ) {
+ *s = TOLOWER( (unsigned char) *s );
+ }
}
return( str );