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By using different variable names globally and locally, the compiler forces the developer to be more precise and descriptive with variable names.

Exceptions

DCL01-EX0EX1: A function argument in a function declaration may clash with a variable in a containing scope provided that when the function is defined, the argument has a name that clashes with no variables in any containing scopes.

extern int name;
void f(char *name);  /* Declaration: no problem here */
/* ... */
void f(char *arg) {  /* Definition: no problem; arg doesn't hide name */
  /* Use arg */
}

DCL01-EX1EX2: A temporary variable within a new scope inside of a macro can override a surrounding identifier.

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