CURLOPT_PREREQFUNCTION(3) Library Functions Manual CURLOPT_PREREQFUNCTION(3)
NAME
CURLOPT_PREREQFUNCTION - user callback called when a connection has
been established, but before a request has been made.
SYNOPSIS
#include <curl/curl.h>
/* These are the return codes for the pre-request callback. */
#define CURL_PREREQFUNC_OK 0
#define CURL_PREREQFUNC_ABORT 1 /* fail the entire transfer */
int prereq_callback(void *clientp,
char *conn_primary_ip,
char *conn_local_ip,
int conn_primary_port,
int conn_local_port);
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PREREQFUNCTION, prereq_callback);
DESCRIPTION
Pass a pointer to your callback function, which should match the
prototype shown above.
This function gets called by libcurl after a connection has been
established or a connection has been reused (including any SSL
handshaking), but before any request is actually made on the
connection. For example, for HTTP, this callback is called once a
connection has been established to the server, but before a
GET/HEAD/POST/etc request has been sent.
This function may be called multiple times if redirections are enabled
and are being followed (see CURLOPT_FOLLOWLOCATION(3)).
The callback function must return CURL_PREREQFUNC_OK on success, or
CURL_PREREQFUNC_ABORT to cause the transfer to fail.
This function is passed the following arguments:
conn_primary_ip
A null-terminated pointer to a C string containing the primary
IP of the remote server established with this connection. For
FTP, this is the IP for the control connection. IPv6 addresses
are represented without surrounding brackets.
conn_local_ip
A null-terminated pointer to a C string containing the
originating IP for this connection. IPv6 addresses are
represented without surrounding brackets.
conn_primary_port
The primary port number on the remote server established with
this connection. For FTP, this is the port for the control
connection. This can be a TCP or a UDP port number depending on
the protocol.
conn_local_port
The originating port number for this connection. This can be a
TCP or a UDP port number depending on the protocol.
clientp
The pointer you set with CURLOPT_PREREQDATA(3).
DEFAULT
NULL
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
struct priv {
void *custom;
};
static int prereq_callback(void *clientp,
char *conn_primary_ip,
char *conn_local_ip,
int conn_primary_port,
int conn_local_port)
{
printf("Connection made to %s:%d\n", conn_primary_ip, conn_primary_port);
return CURL_PREREQFUNC_OK;
}
int main(void)
{
struct priv prereq_data;
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_PREREQFUNCTION, prereq_callback);
curl_easy_setopt(curl, CURLOPT_PREREQDATA, &prereq_data);
curl_easy_perform(curl);
}
}
AVAILABILITY
Added in curl 7.80.0
RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION
if not.
SEE ALSO
CURLINFO_PRIMARY_IP(3), CURLINFO_PRIMARY_PORT(3), CURLOPT_PREREQDATA(3)
libcurl 2024-08-05 CURLOPT_PREREQFUNCTION(3)
curl 8.9.1 - Generated Wed Aug 7 15:29:48 CDT 2024