curl返回值写入内存的场景
直接上代码：
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include <curl/curl.h> 5 6 struct MemoryStruct { 7 char *memory; 8 size_t size; 9 }; 10 11 static size_t 12 WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) 13 { 14 size_t realsize = size * nmemb; 15 struct MemoryStruct *mem = (struct MemoryStruct *)userp; 16 17 mem->memory = (char*)realloc(mem->memory, mem->size + realsize + 1); 18 if(mem->memory == NULL) { 19 /* out of memory! */ 20 printf("not enough memory (realloc returned NULL)\n"); 21 return 0; 22 } 23 24 memcpy(&(mem->memory[mem->size]), contents, realsize); 25 mem->size += realsize; 26 mem->memory[mem->size] = 0; 27 28 return realsize; 29 } 30 int main(void) 31 { 32 CURL *curl; 33 CURLcode res; 34 struct MemoryStruct chunk; 35 static const char *postthis="Field=1&Field=2&Field=3"; 36 37 chunk.memory = (char*)malloc(1); /* will be grown as needed by realloc above */ 38 chunk.size = 0; /* no data at this point */ 39 40 curl_global_init(CURL_GLOBAL_ALL); 41 curl = curl_easy_init(); 42 if(curl) { 43 44 curl_easy_setopt(curl, CURLOPT_URL, "http://www.example.org/"); 45 46 /* send all data to this function */ 47 curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback); 48 49 /* we pass our 'chunk' struct to the callback function */ 50 curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk); 51 52 /* some servers don't like requests that are made without a user-agent 53 field, so we provide one */ 54 curl_easy_setopt(curl, CURLOPT_USERAGENT, "libcurl-agent/1.0"); 55 56 curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postthis); 57 58 /* if we don't provide POSTFIELDSIZE, libcurl will strlen() by 59 itself */ 60 curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis)); 61 62 /* Perform the request, res will get the return code */ 63 res = curl_easy_perform(curl); 64 /* Check for errors */ 65 if(res != CURLE_OK) { 66 fprintf(stderr, "curl_easy_perform() failed: %s\n", 67 curl_easy_strerror(res)); 68 } 69 else { 70 /* 71 * Now, our chunk.memory points to a memory block that is chunk.size 72 * bytes big and contains the remote file. 73 * 74 * Do something nice with it! 75 */ 76 printf("%s\n",chunk.memory); 77 } 78 79 /* always cleanup */ 80 curl_easy_cleanup(curl); 81 82 free(chunk.memory); 83 84 /* we're done with libcurl, so clean it up */ 85 curl_global_cleanup(); 86 } 87 return 0; 88 }
