top level `continue` in nested loop C instead of current level loop

Question

How do I make continue goes to the top level of loop? I mean like this:

for(;;){ // top level loop
   statement1;
   for(;;){ // second level loop
      statement2;
      if (condition1){
         continue; // I expect it continue to the start of top level so it will execute statement1.
      }
   }
   statement3;
}

This is my real case why I got problem above, basically my program is sending data with UDP socket which the data should be sent fast. I know UDP is unrealiable but it's okay the data is tolerated with loss too.

 for (;;) {  // Streaming data...
    camera_fb_t* fb = esp_camera_fb_get();
    size_t quotient = fb ->len / UDP_BUF_SIZE;
    size_t remainder = fb ->len % UDP_BUF_SIZE;
    unsigned int i = 0;
    for (; i < quotient; i++) {  // sending packet by packet.
      if (uwc_udp_send_raw((const void*)(fb ->buf + (i * UDP_BUF_SIZE)),
                           UDP_BUF_SIZE) < 0) {
        ESP_LOGE(uwc_tag_event, "Error in iteration: %i", i);
        uwc_udp_send_raw("ERR",3); // Tell receiver there was corrupt during send data.
        esp_camera_fb_return(fb);
        continue; // I expect it continue to the top level
      }
    }
    if (remainder) {  // last packet to be sent if remainder exist
      uwc_udp_send_raw((const void*)(fb ->buf + (i * UDP_BUF_SIZE)),
                       remainder);
      ESP_LOGE(uwc_tag_event, "Error in last iteration!");
    }
    esp_camera_fb_return(fb);
  }

Answer 1

You don't need a flag or continue or goto:

for (;;) {
    camera_fb_t *uwcCamFb = esp_camera_fb_get();
    unsigned char *from = uwcCamFb->buf;
    size_t toSend = uwcCamFb->len;

    for( int i = 0; toSend > 0; i++ ) {
        size_t sendSize = toSend > UDP_BUF_SIZE ? UDP_BUF_SIZE : toSend;
        if( uwc_udp_send_raw( from, sendSize ) < 0) {
            ESP_LOGE( uwc_tag_event, "Error in iteration: %i", i );
            uwc_udp_send_raw( "ERR", 3 );
            break;
        }
        toSend -= sendSize;
        from += sendSize;
    }
    // Update...
    // Removed conditional as it reflected flawed OP logic...
    // if( toSend == 0 )
        esp_camera_fb_return( uwcCamFb );
}

If you need/want to distinguish the LAST packet, add if( toSend < UDP_BUF_SIZE ) to log that particular error message instead...

It seems your OP used both fb and uwcCamFb... I can only guess this corrects that apparently mistake...

(Thank you to @Persixty for a bug report that has been fixed.)