NAME¶

std::gets - std::gets

Synopsis¶

Defined in header <cstdio>
char* gets( char* str ); (deprecated in C++11)
(removed in C++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 C++11 and removed altogether in C++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¶

scanf reads formatted input from stdin, a file stream or a buffer
fscanf (function)
sscanf
fgets gets a character string from a file stream
(function)
fputs writes a character string to a file stream
(function)
C documentation for
gets