1---
2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
3SPDX-License-Identifier: curl
4Title: CURLOPT_ERRORBUFFER
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_DEBUGFUNCTION (3)
9  - CURLOPT_VERBOSE (3)
10  - curl_easy_strerror (3)
11  - curl_multi_strerror (3)
12  - curl_share_strerror (3)
13  - curl_url_strerror (3)
14---
15
16# NAME
17
18CURLOPT_ERRORBUFFER - error buffer for error messages
19
20# SYNOPSIS
21
22~~~c
23#include <curl/curl.h>
24
25CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ERRORBUFFER, char *buf);
26~~~
27
28# DESCRIPTION
29
30Pass a char pointer to a buffer that libcurl may use to store human readable
31error messages on failures or problems. This may be more helpful than just the
32return code from curl_easy_perform(3) and related functions. The buffer must
33be at least **CURL_ERROR_SIZE** bytes big.
34
35You must keep the associated buffer available until libcurl no longer needs
36it. Failing to do so might cause odd behavior or even crashes. libcurl might
37need it until you call curl_easy_cleanup(3) or you set the same option
38again to use a different pointer.
39
40Do not rely on the contents of the buffer unless an error code was returned.
41Since 7.60.0 libcurl initializes the contents of the error buffer to an empty
42string before performing the transfer. For earlier versions if an error code
43was returned but there was no error detail then the buffer was untouched.
44
45Consider CURLOPT_VERBOSE(3) and CURLOPT_DEBUGFUNCTION(3) to better
46debug and trace why errors happen.
47
48# DEFAULT
49
50NULL
51
52# PROTOCOLS
53
54All
55
56# EXAMPLE
57
58~~~c
59#include <string.h> /* for strlen() */
60int main(void)
61{
62  CURL *curl = curl_easy_init();
63  if(curl) {
64    CURLcode res;
65    char errbuf[CURL_ERROR_SIZE];
66
67    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
68
69    /* provide a buffer to store errors in */
70    curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errbuf);
71
72    /* set the error buffer as empty before performing a request */
73    errbuf[0] = 0;
74
75    /* perform the request */
76    res = curl_easy_perform(curl);
77
78    /* if the request did not complete correctly, show the error
79    information. if no detailed error information was written to errbuf
80    show the more generic information from curl_easy_strerror instead.
81    */
82    if(res != CURLE_OK) {
83      size_t len = strlen(errbuf);
84      fprintf(stderr, "\nlibcurl: (%d) ", res);
85      if(len)
86        fprintf(stderr, "%s%s", errbuf,
87                ((errbuf[len - 1] != '\n') ? "\n" : ""));
88      else
89        fprintf(stderr, "%s\n", curl_easy_strerror(res));
90    }
91  }
92}
93~~~
94
95# AVAILABILITY
96
97Always
98
99# RETURN VALUE
100
101Returns CURLE_OK
102