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                     23: .TH CURLOPT_ERRORBUFFER 3 "March 23, 2020" "libcurl 7.70.0" "curl_easy_setopt options"
                     24: 
                     25: .SH NAME
                     26: CURLOPT_ERRORBUFFER \- set error buffer for error messages
                     27: .SH SYNOPSIS
                     28: #include <curl/curl.h>
                     29: 
                     30: CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ERRORBUFFER, char *buf);
                     31: .SH DESCRIPTION
                     32: Pass a char * to a buffer that libcurl \fBmay\fP store human readable error
                     33: messages on failures or problems. This may be more helpful than just the
                     34: return code from \fIcurl_easy_perform(3)\fP and related functions. The buffer
                     35: \fBmust be at least CURL_ERROR_SIZE bytes big\fP.
                     36: 
                     37: You must keep the associated buffer available until libcurl no longer needs
                     38: it. Failing to do so will cause very odd behavior or even crashes. libcurl
                     39: will need it until you call \fIcurl_easy_cleanup(3)\fP or you set the same
                     40: option again to use a different pointer.
                     41: 
                     42: Do not rely on the contents of the buffer unless an error code was returned.
                     43: Since 7.60.0 libcurl will initialize the contents of the error buffer to an
                     44: empty string before performing the transfer. For earlier versions if an error
                     45: code was returned but there was no error detail then the buffer is untouched.
                     46: 
                     47: Consider \fICURLOPT_VERBOSE(3)\fP and \fICURLOPT_DEBUGFUNCTION(3)\fP to better
                     48: debug and trace why errors happen.
                     49: .SH DEFAULT
                     50: NULL
                     51: .SH PROTOCOLS
                     52: All
                     53: .SH EXAMPLE
                     54: .nf
                     55: curl = curl_easy_init();
                     56: if(curl) {
                     57:   CURLcode res;
                     58:   char errbuf[CURL_ERROR_SIZE];
                     59: 
                     60:   curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
                     61: 
                     62:   /* provide a buffer to store errors in */
                     63:   curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, errbuf);
                     64: 
                     65:   /* set the error buffer as empty before performing a request */
                     66:   errbuf[0] = 0;
                     67: 
                     68:   /* perform the request */
                     69:   res = curl_easy_perform(curl);
                     70: 
                     71:   /* if the request did not complete correctly, show the error
                     72:   information. if no detailed error information was written to errbuf
                     73:   show the more generic information from curl_easy_strerror instead.
                     74:   */
                     75:   if(res != CURLE_OK) {
                     76:     size_t len = strlen(errbuf);
                     77:     fprintf(stderr, "\\nlibcurl: (%d) ", res);
                     78:     if(len)
                     79:       fprintf(stderr, "%s%s", errbuf,
                     80:               ((errbuf[len - 1] != '\\n') ? "\\n" : ""));
                     81:     else
                     82:       fprintf(stderr, "%s\\n", curl_easy_strerror(res));
                     83:   }
                     84: }
                     85: .fi
                     86: .SH AVAILABILITY
                     87: Always
                     88: .SH RETURN VALUE
                     89: Returns CURLE_OK
                     90: .SH "SEE ALSO"
                     91: .BR CURLOPT_DEBUGFUNCTION "(3), " CURLOPT_VERBOSE "(3), "
                     92: .BR curl_easy_strerror "(3), " curl_multi_strerror "(3), "
                     93: .BR curl_share_strerror "(3) "