std::ferror (3) Linux Manual Page

std::ferror – std::ferror

Synopsis

Defined in header<cstdio>

    int ferror(std::FILE *stream);

Checks the given stream for errors.

Parameters

stream – the file stream to check

Return value

Nonzero value if the file stream has errors occurred, 0 otherwise

Example

// Run this code

#include <cstdio>

#include <cstdlib>

#include <clocale>

#include <cwchar>
int main(void)

{
    const char *fname = std::tmpnam(nullptr);
    std::FILE *f = std::fopen(fname, "wb");
    std::fputs("\xff\xff\n", f); // not a valid UTF-8 character sequence
    std::fclose(f);
    std::setlocale(LC_ALL, "en_US.utf8");
    f = std::fopen(fname, "rb");
    std::wint_t ch;
    while ((ch = std::fgetwc(f)) != WEOF) // attempt to read as UTF-8
        std::printf("%#x ", ch);
    if (std::feof(f))
        puts("EOF indicator set");
    if (std::ferror(f))
        puts("Error indicator set");
}

Output:

  Error indicator set

See also

         clears errors
clearerr (function)
         checks for the end-of-file
feof (function)
         checks if an error has occurred
fail (public member function of std::basic_ios<CharT,Traits>)