798a37b25e
- Clear data->state.os_errno before transfer. - Explain the change in behavior in the CURLINFO_OS_ERRNO doc. - Add to the CURLINFO_OS_ERRNO doc the list of libcurl network-related errors that may cause the errno to be saved. data->state.os_errno is saved before libcurl returns a network-related failure such as connection failure. It is accessible to the user via CURLINFO_OS_ERRNO so they can get more information about the failure. Prior to this change it wasn't cleared before transfer, so if a user retrieved the saved errno it could be from a previous transfer. That is because an errno is not always saved for network-related errors. Closes https://github.com/curl/curl/pull/13574
69 lines
1.6 KiB
Markdown
69 lines
1.6 KiB
Markdown
---
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c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLINFO_OS_ERRNO
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Section: 3
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Source: libcurl
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See-also:
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- curl_easy_getinfo (3)
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- curl_easy_setopt (3)
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Protocol:
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- All
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---
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# NAME
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CURLINFO_OS_ERRNO - get errno number from last connect failure
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_OS_ERRNO, long *errnop);
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~~~
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# DESCRIPTION
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Pass a pointer to a long to receive the errno variable from a connect failure.
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Note that the value is only set on failure, it is not reset upon a successful
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operation. The number is OS and system specific.
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libcurl network-related errors that may have a saved errno are:
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CURLE_COULDNT_CONNECT, CURLE_FAILED_INIT, CURLE_INTERFACE_FAILED,
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CURLE_OPERATION_TIMEDOUT, CURLE_RECV_ERROR, CURLE_SEND_ERROR.
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Since 8.8.0 libcurl clears the easy handle's saved errno before performing the
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transfer. Prior versions did not clear the saved errno, which means if a saved
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errno is retrieved it could be from a previous transfer on the same handle.
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURL *curl = curl_easy_init();
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if(curl) {
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CURLcode res;
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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res = curl_easy_perform(curl);
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if(res != CURLE_OK) {
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long error;
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res = curl_easy_getinfo(curl, CURLINFO_OS_ERRNO, &error);
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if(!res && error) {
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printf("Errno: %ld\n", error);
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}
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}
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curl_easy_cleanup(curl);
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}
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}
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~~~
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# AVAILABILITY
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Added in 7.12.2
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# RETURN VALUE
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Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
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