curl_easy_perform.3

harvest是一个下载html网页得机器人

.\" You can view this file with:
.\" nroff -man [file]
.\" $Id: curl_easy_perform.3,v 1.1 2002/03/04 10:09:49 bagder Exp $
.\"
.TH curl_easy_perform 3 "5 Mar 2001" "libcurl 7.7" "libcurl Manual"
.SH NAME
curl_easy_perform - Perform a file transfer
.SH SYNOPSIS
.B #include <curl/curl.h>
.sp
.BI "CURLcode curl_easy_perform(CURL *" handle ");
.ad
.SH DESCRIPTION
This function is called after the init and all the curl_easy_setopt() calls
are made, and will perform the transfer as described in the options.
It must be called with the same
.I handle
as input as the curl_easy_init call returned.

libcurl version 7.7 or later (for older versions see below): You can do any
amount of calls to curl_easy_perform() while using the same handle. If you
intend to transfer more than one file, you are even encouraged to do
so. libcurl will then attempt to re-use the same connection for the following
transfers, thus making the operations faster, less CPU intense and using less
network resources. Just note that you will have to use
.I curl_easy_setopt
between the invokes to set options for the following curl_easy_perform.

You must never call this function simultaneously from two places using the
same handle. Let the function return first before invoking it another time. If
you want parallel transfers, you must use several curl handles.

Before libcurl version 7.7: You are only allowed to call this function once
using the same handle. If you want to do repeated calls, you must call
curl_easy_cleanup and curl_easy_init again first.
.SH RETURN VALUE
0 means everything was ok, non-zero means an error occurred as
.I <curl/curl.h>
defines. If the CURLOPT_ERRORBUFFER was set with
.I curl_easy_setopt
there will be a readable error message in the error buffer when non-zero is
returned.
.SH "SEE ALSO"
.BR curl_easy_init "(3), " curl_easy_setopt "(3), "
.SH BUGS
Surely there are some, you tell me!