CURLINFO_OS_ERRNO(3) Library Functions Manual CURLINFO_OS_ERRNO(3) NAME CURLINFO_OS_ERRNO - get errno number from last connect failure SYNOPSIS #include CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_OS_ERRNO, long *errnop); DESCRIPTION Pass a pointer to a long to receive the errno variable from a connect failure. Note that the value is only set on failure, it is not reset upon a successful operation. The number is OS and system specific. libcurl network-related errors that may have a saved errno are: CURLE_COULDNT_CONNECT, CURLE_FAILED_INIT, CURLE_INTERFACE_FAILED, CURLE_OPERATION_TIMEDOUT, CURLE_RECV_ERROR, CURLE_SEND_ERROR. Since 8.8.0 libcurl clears the easy handle's saved errno before performing the transfer. Prior versions did not clear the saved errno, which means if a saved errno is retrieved it could be from a previous transfer on the same handle. PROTOCOLS This functionality affects all supported protocols EXAMPLE int main(void) { CURL *curl = curl_easy_init(); if(curl) { CURLcode res; curl_easy_setopt(curl, CURLOPT_URL, "https://example.com"); res = curl_easy_perform(curl); if(res != CURLE_OK) { long error; res = curl_easy_getinfo(curl, CURLINFO_OS_ERRNO, &error); if(!res && error) { printf("Errno: %ld\n", error); } } curl_easy_cleanup(curl); } } AVAILABILITY Added in curl 7.12.2 RETURN VALUE curl_easy_getinfo(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). SEE ALSO curl_easy_getinfo(3), curl_easy_setopt(3) libcurl 2025-02-08 CURLINFO_OS_ERRNO(3)