Difference between 'strcpy' and 'strcpy_s'?

c++, strcpy, visual-c++, windows

Solution

`strcpy` is a unsafe function. When you try to copy a string using `strcpy()` to a buffer which is not large enough to contain it, it will cause a buffer overflow.

`strcpy_s()` is a security enhanced version of `strcpy()`. With `strcpy_s` you can specify the size of the destination buffer to avoid buffer overflows during copies.

char tuna[5];  // a buffer which holds 5 chars incluing the null character.
char salmon[] = "A string which is longer than 5 chars";

strcpy( tuna, salmon ); // This will corrupt your memory because of the buffer overflow.

strcpy_s( tuna, 5, salmon ); // strcpy_s will not write more than 5 chars.

Problem

When I tried to use `strcpy` to copy a string it gave me a compile error. ``` error C4996 'strcpy': This function or variable may be unsafe. Consider using `strcpy_s` instead. To disable deprecation, use `_CRT_SECURE_NO_WARNINGS`. See online help for details. ``` What is the difference between `strcpy` and `strcpy_s`?

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