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Whats wrong with casting mallocs return value?

April 26, 2017casting malloc Return value wrong

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Whats wrong with casting mallocs return value?

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Suppose that you call malloc but forget to #include . The compiler is likely to assume that malloc is a function returning int, which is of course incorrect, and will lead to trouble. Now, if your call to malloc is of the form char *p = malloc(10); the compiler will notice that you’re seemingly assigning an integer to a pointer, and will likely emit a warning of the form “assignment of pointer from integer lacks a cast” (see question 7.6), which will alert you to the problem. (The problem is of course that you forgot to #include , not that you forgot to use a cast.) If, on the other hand, your call to malloc includes a cast: char *p = (char *)malloc(10); the compiler is likely to assume that you know what you’re doing, that you really do want to convert the int returned by malloc to a pointer, and the compiler therefore probably won’t warn you. But of course malloc does not return an int, so trying to convert the int that it doesn’t return to a pointer is likely t