romenskiy2012/curl

mirror of https://github.com/curl/curl.git synced 2026-08-24 19:13:39 +03:00

docs: make 5 example snippets compile cleanly with clang

verify-examples.pl invokes 'gcc', which on macOS is clang. With
-Wall -Wextra... -Werror -pedantic, clang rejects two patterns that
GNU gcc accepts:

- passing a char * to %p without a cast (-Wformat-pedantic): the C
  standard says %p expects void *, so cast explicitly in the
  CURLOPT_PROGRESSDATA, CURLOPT_PROGRESSFUNCTION, CURLOPT_XFERINFODATA
  and CURLOPT_XFERINFOFUNCTION examples

- returning CURLcode result from main() when curl_easy_init() returned
  NULL leaves it uninitialized (-Wsometimes-uninitialized) in the
  CURLINFO_TLS_SSL_PTR example: initialize it to CURLE_OK like other
  man pages already do

Closes #22638

2026-08-22 16:18:50 +02:00

1.6 KiB

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SPDX-License-Identifier

Title

Section

Source

See-also

Protocol

Added-in

curl

CURLOPT_XFERINFODATA

libcurl

CURLOPT_NOPROGRESS (3)

CURLOPT_VERBOSE (3)

CURLOPT_XFERINFOFUNCTION (3)

All

7.32.0

NAME

CURLOPT_XFERINFODATA - pointer passed to the progress callback

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_XFERINFODATA, void *pointer);

DESCRIPTION

Pass a pointer that is untouched by libcurl and passed as the first argument in the progress callback set with CURLOPT_XFERINFOFUNCTION(3).

This is an alias for CURLOPT_PROGRESSDATA(3).

DEFAULT

NULL

%PROTOCOLS%

EXAMPLE

struct progress {
  char *private;
  size_t size;
};

static int progress_cb(void *clientp,
                       curl_off_t dltotal,
                       curl_off_t dlnow,
                       curl_off_t ultotal,
                       curl_off_t ulnow)
{
  struct progress *memory = clientp;
  printf("private ptr: %p\n", (void *)memory->private);
  /* use the values */

  return 0; /* all is good */
}

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    struct progress data;

    /* pass struct to callback */
    curl_easy_setopt(curl, CURLOPT_XFERINFODATA, &data);
    curl_easy_setopt(curl, CURLOPT_XFERINFOFUNCTION, progress_cb);
  }
}

%AVAILABILITY%

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

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