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How To Use Libcurl In Your Program:
(by Ralph Beckmann <rabe@uni-paderborn.de>)
NOTE: If you plan to use libcurl.a in Threads under Linux, do not use the old
gcc-2.7.x because the function 'gethostbyname' seems not to be thread-safe,
that is to say an unavoidable SEGMENTATION FAULT might occur.
1. a) In a C-Program:
#include "curl.h"
b) In a C++-Program:
extern "C" {
#include "curl.h"
}
2. char *url="http://www.domain.com";
curl_urlget (URGTAG_URL, url,
URGTAG_FLAGS, CONF_NOPROGRESS,
URGTAG_ERRORBUFFER, errorBuffer,
URGTAG_WRITEFUNCTION, (size_t (*)(void *, int, int, FILE
*))handle_data,
URGTAG_TIMEOUT, 30, /* or anything You want */
...
URGTAG_DONE);
3. size_t handle_data (const void *ptr, size_t size, size_t nitems,
FILE *stream)
{
(void)stream; /* stop complaining using g++ -Wall */
if ((int)nitems <= 0) {
return (size_t)0;
}
fprintf(stdout, (char *)ptr); /* or do anything else with it */
return nitems;
}
4. Compile Your Program with -I$(CURL_DIR)/include
5. Link Your Program together with $(CURL_DIR)/lib/libcurl.a
Small Example of How To Use libcurl
----------------------------------------------------------------------
/* Full example that uses libcurl.a to fetch web pages. */
/* curlthreads.c */
/* - Test-Program by Ralph Beckmann for using curl in POSIX-Threads */
/* Change *url1 and *url2 to textual long and slow non-FRAMESET websites! */
/*
1. Compile with gcc or g++ as $(CC):
$(CC) -c -Wall -pedantic curlthreads.c -I$(CURL_DIR)/include
2. Link with:
- Linux:
$(CC) -o curlthreads curlthreads.o $(CURL_DIR)/lib/libcurl.a -lpthread
-lm
- Solaris:
$(CC) -o curlthreads curlthreads.o $(CURL_DIR)/lib/libcurl.a -lpthread
-lm -lsocket -lnsl
*/
#include <pthread.h>
#include <stdio.h>
#ifdef __cplusplus
extern "C" {
#include "curl.h"
}
#else
#include "curl.h"
#endif
size_t storedata (const void *ptr, size_t size, size_t nitems, FILE *stream) {
(void)ptr; (void)stream; /* just to stop g++ -Wall complaining */
fprintf(stdout, "Thread #%i reads %i Bytes.\n",
(int)pthread_self(), (int)(nitems*size));
return (nitems);
}
void *urlfetcher(void *url) {
curl_urlget (URGTAG_URL, url,
URGTAG_FLAGS, CONF_NOPROGRESS | CONF_FAILONERROR,
URGTAG_WRITEFUNCTION, (size_t (*)(void *, int, int, FILE
*))storedata,
URGTAG_DONE);
return NULL;
}
int main(void) {
char *url1="www.sun.com";
char *url2="www.microsoft.com";
pthread_t thread_id1, thread_id2;
pthread_create(&thread_id1, NULL, urlfetcher, (void *)url1);
pthread_create(&thread_id2, NULL, urlfetcher, (void *)url2);
pthread_join(thread_id1, NULL);
pthread_join(thread_id2, NULL);
fprintf(stdout, "Ready.\n");
return 0;
}
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