How to use strcpy_s in c++

The strcpy_s function is used to safely copy the string src to the string dst. Its syntax is: check the validity of the parameters. Call strcpy_s to copy src into dst. Check the return value to ensure that the copy was successful or that the target string was too small.

Usage of strcpy_s function in C

strcpy_s function is used to copy one string to another character string, it is better than the strcpy function in safely copying strings.

Syntax:

<code class="cpp">errno_t strcpy_s(char* dst, size_t dstSize, const char* src);</code>

Parameters:

• dst: of the target string address.
• dstSize: The maximum size of the target string (including null characters).
• src: The address of the source string.

Return value:

• 0: Copied successfully.
• ERANGE: The destination string is too small to accommodate the source string.
• EINVAL: The parameter is invalid.

Usage:

1. Check parameters: Make sure dst and src Points to a valid string and dstSize is large enough to accommodate the source string.
2. Call strcpy_s: Copy the source string to the destination string.
3. Check the return value: If the return value is ERANGE, it means that the target string is too small and dstSize needs to be adjusted.

Example:

<code class="cpp">char dst[100];
const char* src = "Hello, world!";

strcpy_s(dst, sizeof(dst), src);

std::cout << dst << std::endl; // 输出 "Hello, world!"</code>

Note:

• strcpy_s will automatically be at the end of the target string Add the null character '\0'.
• If dst is nullptr, src is nullptr, or dstSize is 0, then strcpy_s will return EINVAL.
• dstSize The parameter must include the null character, otherwise strcpy_s may cause a buffer overflow.

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