[WIP] Making a HTTP request using cURL in Zig.

main.zig

const c = @cImport({
    @cInclude("curl/curl.h");
    @cInclude("stdlib.h");
    @cInclude("stddef.h");
});
const std = @import("std");

// XXX Trying to use c.size_t from stddef.h results in
//     "container … has no member called 'size_t'".
//
//     I *think* this is right.
const size_t = if (@typeInfo(usize).Int.bits == 64) u64 else u32;

fn ok(code: c.CURLcode) void {
    if (code != @intToEnum(c.CURLcode, c.CURLE_OK)) {
        // TODO: It would be better if this said something like: "cURL error: <error text>".
        @panic(std.mem.span(c.curl_easy_strerror(code)));
    }
}

fn write_data(buffer: *c_void, size: size_t, nmemb: size_t, userp: *c_void) callconv(.C) size_t {
    // Size is always 1.

    // TODO: get the data from buffer
    // TODO: are we responsible for freeing buffer?
    return ziggy_write_data(buffer, nmemb, userp);
}

/// A more "ziggy" version of write_data.
fn ziggy_write_data(buffer: *c_void, nmemb: size_t, userp: *c_void) size_t {
    std.debug.print("nmemb: {}\n", .{nmemb});

    return nmemb;
}

pub fn main() void {
    ok(c.curl_global_init(c.CURL_GLOBAL_ALL));
    defer c.curl_global_cleanup();

    const handle = c.curl_easy_init();
    defer c.curl_easy_cleanup(handle);

    ok(c.curl_easy_setopt(handle, @intToEnum(c.CURLoption, c.CURLOPT_URL), "htps://www.apple.com"));
    ok(c.curl_easy_setopt(handle, @intToEnum(c.CURLoption, c.CURLOPT_WRITEFUNCTION), write_data));

    ok(c.curl_easy_perform(handle));
}