NAME

       CURLOPT_DEBUGFUNCTION - debug callback

SYNOPSIS

       #include <curl/curl.h>

       typedef enum {
         CURLINFO_TEXT = 0,
         CURLINFO_HEADER_IN,    /* 1 */
         CURLINFO_HEADER_OUT,   /* 2 */
         CURLINFO_DATA_IN,      /* 3 */
         CURLINFO_DATA_OUT,     /* 4 */
         CURLINFO_SSL_DATA_IN,  /* 5 */
         CURLINFO_SSL_DATA_OUT, /* 6 */
         CURLINFO_END
       } curl_infotype;

       int debug_callback(CURL *handle,
                          curl_infotype type,
                          char *data,
                          size_t size,
                          void *userptr);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DEBUGFUNCTION,
                                 debug_callback);

DESCRIPTION

       Pass a pointer to your callback function, which should match the prototype shown above.

       CURLOPT_DEBUGFUNCTION(3) replaces the standard debug function used when CURLOPT_VERBOSE(3)
       is in effect. This callback receives debug information, as specified in the type argument.
       This  function  must  return  0. The data pointed to by the char * passed to this function
       WILL NOT be null-terminated, but will be exactly of the size as told by the size argument.

       The userptr argument is the pointer set with CURLOPT_DEBUGDATA(3).

       Available curl_infotype values:

       CURLINFO_TEXT
              The data is informational text.

       CURLINFO_HEADER_IN
              The data is header (or header-like) data received from the peer.

       CURLINFO_HEADER_OUT
              The data is header (or header-like) data sent to the peer.

       CURLINFO_DATA_IN
              The data is protocol data received from the peer.

       CURLINFO_DATA_OUT
              The data is protocol data sent to the peer.

       CURLINFO_SSL_DATA_OUT
              The data is SSL/TLS (binary) data sent to the peer.

       CURLINFO_SSL_DATA_IN
              The data is SSL/TLS (binary) data received from the peer.

DEFAULT

       NULL

PROTOCOLS

       All

EXAMPLE

       static
       void dump(const char *text,
                 FILE *stream, unsigned char *ptr, size_t size)
       {
         size_t i;
         size_t c;
         unsigned int width=0x10;

         fprintf(stream, "%s, %10.10ld bytes (0x%8.8lx)\n",
                 text, (long)size, (long)size);

         for(i=0; i<size; i+= width) {
           fprintf(stream, "%4.4lx: ", (long)i);

           /* show hex to the left */
           for(c = 0; c < width; c++) {
             if(i+c < size)
               fprintf(stream, "%02x ", ptr[i+c]);
             else
               fputs("   ", stream);
           }

           /* show data on the right */
           for(c = 0; (c < width) && (i+c < size); c++) {
             char x = (ptr[i+c] >= 0x20 && ptr[i+c] < 0x80) ? ptr[i+c] : '.';
             fputc(x, stream);
           }

           fputc('\n', stream); /* newline */
         }
       }

       static
       int my_trace(CURL *handle, curl_infotype type,
                    char *data, size_t size,
                    void *userp)
       {
         const char *text;
         (void)handle; /* prevent compiler warning */
         (void)userp;

         switch (type) {
         case CURLINFO_TEXT:
           fprintf(stderr, "== Info: %s", data);
         default: /* in case a new one is introduced to shock us */
           return 0;

         case CURLINFO_HEADER_OUT:
           text = "=> Send header";
           break;
         case CURLINFO_DATA_OUT:
           text = "=> Send data";
           break;
         case CURLINFO_SSL_DATA_OUT:
           text = "=> Send SSL data";
           break;
         case CURLINFO_HEADER_IN:
           text = "<= Recv header";
           break;
         case CURLINFO_DATA_IN:
           text = "<= Recv data";
           break;
         case CURLINFO_SSL_DATA_IN:
           text = "<= Recv SSL data";
           break;
         }

         dump(text, stderr, (unsigned char *)data, size);
         return 0;
       }

       int main(void)
       {
         CURL *curl;
         CURLcode res;

         curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, my_trace);

           /* the DEBUGFUNCTION has no effect until we enable VERBOSE */
           curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);

           /* example.com is redirected, so we tell libcurl to follow redirection */
           curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);

           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
           res = curl_easy_perform(curl);
           /* Check for errors */
           if(res != CURLE_OK)
             fprintf(stderr, "curl_easy_perform() failed: %s\n",
                     curl_easy_strerror(res));

           /* always cleanup */
           curl_easy_cleanup(curl);
         }
         return 0;
       }

AVAILABILITY

       Always

RETURN VALUE

       Returns CURLE_OK

SEE ALSO

       CURLOPT_VERBOSE(3), CURLOPT_DEBUGDATA(3),