std::feof (3) - Linux Manuals

std::feof: std::feof

NAME

std::feof - std::feof

Synopsis

Defined in header <cstdio>
int feof( std::FILE* stream );

Checks if the end of the given file stream has been reached.

Parameters

stream - the file stream to check

Return value

Nonzero value if the end of the stream has been reached, otherwise 0.

Notes

This function only reports the stream state as reported by the most recent I/O operation, it does not examine the associated data source. For example, if the most recent I/O was a std::fgetc, which returned the last byte of a file, std::feof returns zero. The next std::fgetc fails and changes the stream state to end-of-file. Only then std::feof returns non-zero.
In typical usage, input stream processing stops on any error; feof and std::ferror are then used to distinguish between different error conditions.

Example

// Run this code

  #include <cstdio>
  #include <cstdlib>

  int main()
  {
      FILE* fp = std::fopen("test.txt", "r");
      if(!fp) {
          std::perror("File opening failed");
          return EXIT_FAILURE;
      }

      int c; // note: int, not char, required to handle EOF
      while ((c = std::fgetc(fp)) != EOF) { // standard C I/O file reading loop
         std::putchar(c);
      }

      if (std::ferror(fp))
          std::puts("I/O error when reading");
      else if (std::feof(fp))
          std::puts("End of file reached successfully");

      std::fclose(fp);
  }