Why is Direct String Literal to `char*` Conversion Allowed in C but Deprecated in C ?

Why String Literal Conversion to 'char*' is Allowed in C but Deprecated in C

In C, it is valid to assign a string literal directly to a 'char*' pointer, as shown below:

char* p = "abc";

However, in C 11 and onwards, this implicit conversion has been removed due to its potential to lead to undefined behavior if the string literal is modified. The C Standard explicitly states in § C.1.1 that the above example is now invalid.

To address this issue, C allows an explicit cast to convert a string literal to a 'char*' pointer. This cast clearly indicates that the programmer understands the potential risks and accepts responsibility for any consequences that may arise.

char* p = (char*)"abc"; // Valid with explicit cast

The explicit cast in C serves two purposes:

1. It suppresses the compiler warning that would otherwise be generated due to the deprecated implicit conversion.
2. It forces the programmer to acknowledge the potential for undefined behavior if the string literal is modified.

However, it is important to note that even with the explicit cast, assigning a string literal to a 'char' pointer is still not considered a best practice in C . The safer approach is to use a 'const char' pointer, which explicitly indicates that the string literal should not be modified:

char const *p = "abc"; // Valid and safe

This guarantees that the string literal will remain unmodified, preventing potential undefined behavior.

In C, the implicit conversion from a string literal to a 'char*' pointer remains valid due to the large amount of legacy code that relies on this behavior. Removing the implicit conversion in C would have broken a significant number of existing programs.

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