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.TH CURLOPT_TCP_KEEPALIVE 3 "January 02, 2023" "libcurl 7.88.1" "curl_easy_setopt options"

.SH NAME
CURLOPT_TCP_KEEPALIVE \- TCP keep-alive probing
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TCP_KEEPALIVE, long probe);
.fi
.SH DESCRIPTION
Pass a long. If set to 1, TCP keepalive probes will be sent. The delay and
frequency of these probes can be controlled by the
\fICURLOPT_TCP_KEEPIDLE(3)\fP and \fICURLOPT_TCP_KEEPINTVL(3)\fP options,
provided the operating system supports them. Set to 0 (default behavior) to
disable keepalive probes
.SH DEFAULT
0
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

  /* enable TCP keep-alive for this transfer */
  curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);

  /* keep-alive idle time to 120 seconds */
  curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 120L);

  /* interval time between keep-alive probes: 60 seconds */
  curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);

  curl_easy_perform(curl);
}
.fi
.SH AVAILABILITY
Added in 7.25.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_TCP_KEEPIDLE "(3), " CURLOPT_TCP_KEEPINTVL "(3), "