A byte stream is a file stream whose bytes pass between the external file and the program without text-mode translation. Opening a stream in binary mode preserves each byte as read or written, avoiding changes caused by end-of-line conventions. section 14.4
TAKEAWAY: Use the binary-stream interfaces to move through file data deliberately.
- Open the stream with a binary mode such as "rb", "wb", or "ab"; use the update forms when reading and writing the same stream. section 14.4 section 8.3.2
- Use fread and fwrite to transfer size * nmemb bytes from the current file position, and treat a smaller return value as an error. section 14.4
- Use ftell to inspect the byte position and fseek with SEEK_SET or SEEK_CUR to move within the stream. section 14.4
Copying an object representation
A program can write a large C object’s internal representation with fwrite, later reposition the stream with fseek, and read the bytes back with fread. Binary mode keeps the file contents unmodified; the return counts provide a check that the expected transfer completed. section 14.4
1 size_t fread(void* restrict ptr, size_t size, size_t nmemb,
2 FILE* restrict stream);
3 size_t fwrite(void const*restrict ptr, size_t size, size_t nmemb,
4 FILE* restrict stream);
5 int fseek(FILE* stream, long int offset, int whence);
6 long int ftell(FILE* stream);
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Browse the compact C interface for block transfer and file-position control. section 14.4
