从V调用C函数

#flag -lsqlite3

#include "sqlite3.h"

struct C.sqlite3 
struct C.sqlite3_stmt 

fn C.sqlite3_column_int(C.sqlite_stmt, int) int 

fn main() {
    path := 'sqlite3_users.db' 
    db := &C.sqlite3{} 
    C.sqlite3_open(path.cstr(), &db)

    query := 'select count(*) from users' 
    stmt := &C.sqlite3_stmt{} 
    C.sqlite3_prepare_v2(db, query.cstr(), - 1, &stmt, 0)
    C.sqlite3_step(stmt) 
    nr_users := C.sqlite3_column_int(res, 0)
    C.sqlite3_finalize(res)
    println(nr_users) 
} 

可以使用string(cstring)将C字符串转换为V字符串。

查看socket.v以获取从V调用C代码的示例：

https://github.com/vlang/v/blob/master/vlib/net/socket.v