CURLOPT_PRE_PROXY(3)

1CURLOPT_PRE_PROXY(3)       curl_easy_setopt options       CURLOPT_PRE_PROXY(3)
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NAME

6       CURLOPT_PRE_PROXY - set pre-proxy to use
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SYNOPSIS

9       #include <curl/curl.h>
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11       CURLcode  curl_easy_setopt(CURL  *handle, CURLOPT_PRE_PROXY, char *pre‐
12       proxy);
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DESCRIPTION

15       Set the preproxy to use for the upcoming request. The parameter  should
16       be a char * to a null-terminated string holding the host name or dotted
17       numerical IP address. A numerical IPv6 address must be  written  within
18       [brackets].
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20       To specify port number in this string, append :[port] to the end of the
21       host name. The proxy's port number may optionally be specified with the
22       separate  option  CURLOPT_PROXYPORT(3).  If not specified, libcurl will
23       default to using port 1080 for proxies.
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25       A pre proxy is a SOCKS proxy that curl connects to before  it  connects
26       to  the  HTTP(S)  proxy  specified in the CURLOPT_PROXY option. The pre
27       proxy can only be a SOCKS proxy.
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29       The pre proxy string should be prefixed  with  [scheme]://  to  specify
30       which  kind  of  socks is used. Use socks4://, socks4a://, socks5:// or
31       socks5h:// (the last one to enable socks5 and asking the  proxy  to  do
32       the resolving, also known as CURLPROXY_SOCKS5_HOSTNAME type) to request
33       the specific SOCKS version to be used.  Otherwise  SOCKS4  is  used  as
34       default.
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36       Setting  the  pre  proxy string to "" (an empty string) will explicitly
37       disable the use of a pre proxy.
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39       The application does not have to keep the string around  after  setting
40       this option.
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DEFAULT

43       Default is NULL, meaning no pre proxy is used.
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45       When you set a host name to use, do not assume that there's any partic‐
46       ular single port number used widely for proxies. Specify it!
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PROTOCOLS

49       All except file://. Note that some protocols don't do  very  well  over
50       proxy.
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EXAMPLE

53       CURL *curl = curl_easy_init();
54       if(curl) {
55         curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/file.txt");
56         curl_easy_setopt(curl, CURLOPT_PREPROXY, "socks4://socks-proxy:1080");
57         curl_easy_setopt(curl, CURLOPT_PROXY, "http://proxy:80");
58         curl_easy_perform(curl);
59       }
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AVAILABILITY

62       Added in 7.52.0
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RETURN VALUE

65       Returns CURLE_OK if proxies are supported, CURLE_UNKNOWN_OPTION if not,
66       or CURLE_OUT_OF_MEMORY if there was insufficient heap space.
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