std::gets

 

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Defined in header <cstdio>
char* gets( char* str );		(deprecated in 哋它亢++11) (removed in 哋它亢++14)

Reads stdin into given character string until a newline character is found or end-of-file occurs.

Parameters

str

-

character string to be written

Return value

str on success, a null pointer on failure.

If the failure has been caused by end of file condition, additionally sets the eof indicator (see std::feof()) on stdin. If the failure has been caused by some other error, sets the error indicator (see std::ferror()) on stdin.

Notes

The std::gets() function does not perform bounds checking. Therefore, this function is extremely vulnerable to buffer-overflow attacks. It cannot be used safely (unless the program runs in an environment which restricts what can appear on stdin). For this reason, the function was deprecated in 哋它亢++11 and removed altogether in 哋它亢++14. std::fgets() may be used instead.

Example

Run this code

#include <array>
#include <cstdio>
#include <cstring>
 
int main()
{
    std::puts("Never use std::gets(). Use std::fgets() instead!");
 
    std::array<char, 16> buf;
 
    std::printf("Enter a string:\n>");
 
    if (std::fgets(buf.data(), buf.size(), stdin))
    {
        const auto len = std::strlen(buf.data());
        std::printf(
            "The input string:\n[%s] is %s and has the length %li characters.\n",
            buf.data(), len + 1 < buf.size() ? "not truncated" : "truncated", len
        );
    }
    else if (std::feof(stdin))
    {
        std::puts("Error: the end of stdin stream has been reached.");
    }
    else if (std::ferror(stdin))
    {
        std::puts("I/O error when reading from stdin.");
    }
    else
    {
        std::puts("Unknown stdin error.");
    }
}

Possible output:

Never use std::gets(). Use std::fgets() instead!
Enter a string:
>Living on Earth is expensive, but it does include a free trip around the Sun.
The input string:
[Living on Earth] is truncated and has the length 15 characters.

See also

scanffscanfsscanf	reads formatted input from stdin, a file stream or a buffer (function)
fgets	gets a character string from a file stream (function)
fputs	writes a character string to a file stream (function)