NAME¶

std::rewind - std::rewind

Synopsis¶

Defined in header <cstdio>
void rewind( std::FILE* stream );

Moves the file position indicator to the beginning of the given file stream.

The function is equivalent to std::fseek(stream, 0, SEEK_SET);, except that
end-of-file and error indicators are cleared.

The function drops any effects from previous calls to ungetc.

Parameters¶

stream - file stream to modify

Return value¶

(none)

Example¶

// Run this code

#include <array>
#include <cstdio>

int main()
{
std::FILE* f = std::fopen("file.txt", "w");
for (char ch = '0'; ch <= '9'; ch++)
std::fputc(ch, f);
std::fclose(f);

std::array<char, 20> str;
std::FILE* f2 = std::fopen("file.txt", "r");

const unsigned size1 = std::fread(str.data(), 1, str.size(), f2);
std::puts(str.data());
std::printf("size1 = %u\n", size1);

std::rewind(f2);

const unsigned size2 = std::fread(str.data(), 1, str.size(), f2);
std::puts(str.data());
std::printf("size2 = %u", size2);

std::fclose(f2);
}

Output:¶

0123456789
size1 = 10
0123456789
size2 = 10

See also¶

fseek moves the file position indicator to a specific location in a file
(function)
C documentation for
rewind