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Source Code File 06-02_formupload.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <curl/curl.h>

static size_t read_callback(
    void *ptr,
    size_t size,
    size_t nmemb,
    void *userdata)
{
    FILE *local;
    size_t r;

    local = (FILE *)userdata;
    r = fread(ptr,size,nmemb,local);

    return(r);
}

int main()
{
    char address[] = "https://127.0.0.0/formsub.php";
    char file[] = "report.pdf";
    CURL *curl;
    CURLcode res;
    curl_mime *form = NULL;
    curl_mimepart *field = NULL;
    FILE *fp;

    /* open the file */
    fp = fopen( file, "rb");
    if( fp==NULL )
    {
        fprintf(stderr, "Unable to open %s\n", file);
        exit(1);
    }

    /* initialize curl */
    curl = curl_easy_init();
    
    /* create the form */
    form = curl_mime_init(curl);
        /* add the file field */
    field = curl_mime_addpart(form);
    curl_mime_name(field,"file");
    curl_mime_filedata(field,file);

    /* set curl options */
    curl_easy_setopt(curl, CURLOPT_MIMEPOST,form);
    curl_easy_setopt(curl, CURLOPT_READFUNCTION,
            read_callback);
    curl_easy_setopt(curl, CURLOPT_READDATA,fp);
    curl_easy_setopt(curl, CURLOPT_URL,address);

    /* send the form to the page */
    res = curl_easy_perform(curl);
    if( res!=CURLE_OK )
    {
        fprintf(stderr, "failed: %s\n",
                curl_easy_strerror(res));
        exit(1);
    }

    /* cleanup */
    curl_easy_cleanup(curl);
        /* release the form */
    curl_mime_free(form);
        /* and close the file */
    fclose(fp);

    return(0);
}

Notes

* The address[] string is a placeholder, as are the filename and field names.

* Wide version of this code (statements not split)