Function writeall

tools/comdb2ar/util.cpp:157–178

ssize_t writeall(int fd, const void *buf, size_t nbytes)
// Write all the bytes to the given fd.  Return the number of bytes written,
// or -1 if we hit an error or 0 if we can't write (in which case it is
// possible that some bytes were written successfully; we just don't say how
// many to the caller).  Returns nbytes on success.
{
    const char *cbuf = static_cast<const char *>(buf);
    size_t total = 0;

    while(nbytes > 0) {
        ssize_t byteswritten = write(fd, cbuf, nbytes);
        if(byteswritten <= 0) {
            return byteswritten;
        }

        cbuf += byteswritten;
        nbytes -= byteswritten;
        total += byteswritten;
    }

    return total;
}


ssize_t readall(int fd, void *buf, size_t nbytes)