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Top Forums Programming pass a pointer-to-pointer, or return a pointer? Post 302273855 by aaronwong on Tuesday 6th of January 2009 02:03:32 AM
Old 01-06-2009
Quote:
Originally Posted by steephen
Why are you using the function in this scenario? By using function calls you are creating the overhead of function call and temporaray object.
I just want to know the advantages and disadvantages of those two methods by this simple example... actually, in practice, especially in memory management application for a special or embedded system, it is necessary to implement our own function to malloc a block of memory. Then the case raises.
 

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CURLOPT_READDATA(3)					     curl_easy_setopt options					       CURLOPT_READDATA(3)

NAME
CURLOPT_READDATA - custom pointer passed to the read callback SYNOPSIS
#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_READDATA, void *pointer); DESCRIPTION
Data pointer to pass to the file read function. If you use the CURLOPT_READFUNCTION(3) option, this is the pointer you'll get as input in the 4th argument to the callback. If you don't specify a read callback but instead rely on the default internal read function, this data must be a valid readable FILE * (cast to 'void *'). If you're using libcurl as a win32 DLL, you MUST use a CURLOPT_READFUNCTION(3) if you set this option. DEFAULT
By default, this is a FILE * to stdin. PROTOCOLS
This is used for all protocols when sending data. EXAMPLE
CURL *curl = curl_easy_init(); struct MyData this; if(curl) { curl_easy_setopt(curl, CURLOPT_URL, "http://example.com"); /* pass pointer that gets passed in to the CURLOPT_READFUNCTION callback */ curl_easy_setopt(curl, CURLOPT_READDATA, &this); curl_easy_perform(curl); } AVAILABILITY
This option was once known by the older name CURLOPT_INFILE, the name CURLOPT_READDATA(3) was introduced in 7.9.7. RETURN VALUE
This will return CURLE_OK. SEE ALSO
CURLOPT_READFUNCTION(3), CURLOPT_WRITEDATA(3), libcurl 7.54.0 May 01, 2016 CURLOPT_READDATA(3)
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