在我的 vala 項目中找不到 Postgresql

Question

所以我有一個項目，但它使用的是 Vala，很難在社區中找到很多東西，但要通過它。 我有這個項目，可能很簡單，但我發現它現在拖了很長時間。

如何連接到 Postgresql？

我在網上運行了示例代碼：

using GLib;
using Postgres;


public static int main (string[] args)
{
        string conninfo;

        if (args.length > 1) {
                conninfo = args[1];
        } else {
                conninfo = "dbname = postgres";
        }

        /* Make a connection to the database */
        Database conn = Postgres.connect_db (conninfo);

        /* Check to see that the backend connection was successfully made */
        if (conn.get_status () != ConnectionStatus.OK) {
stderr.printf ("Connection to database failed: %s", conn.get_error_message ());
                return 1;
        }

        /*
         * Our test case here involves using a cursor, for which we must be 
inside
         * a transaction block.  We could do the whole thing with a single
         * PQexec() of "select * from pg_database", but that's too trivial to 
make
         * a good example.
         */

        /* Start a transaction block */
        Result res = conn.exec ("BEGIN");
        if (res.get_status () != ExecStatus.COMMAND_OK) {
                stderr.printf ("BEGIN command failed: %s", 
conn.get_error_message ());
                return 1;
        }

        /*
         * Fetch rows from pg_database, the system catalog of databases
         */
        res = conn.exec ("DECLARE myportal CURSOR FOR select * from 
pg_database");
        if (res.get_status () != ExecStatus.COMMAND_OK) {
                stderr.printf ("DECLARE CURSOR failed: %s", 
conn.get_error_message ());
                return 1;
        }

        res = conn.exec ("FETCH ALL in myportal");
        if (res.get_status () != ExecStatus.TUPLES_OK) {
                stderr.printf ("FETCH ALL failed: %s", conn.get_error_message 
());
                return 1;
        }

        /* first, print out the attribute names */
        int nFields = res.get_n_fields ();
        for (int i = 0; i < nFields; i++) {
                stdout.printf ("%-15s", res.get_field_name (i));
        }
        stdout.printf ("\n\n");

        /* next, print out the rows */
        for (int i = 0; i < res.get_n_tuples(); i++) {
                for (int j = 0; j < nFields; j++) {
                        stdout.printf ("%-15s", res.get_value (i, j));
                }
                stdout.printf ("\n");
        }

        ConnectionOptions opt = Postgres.get_default_options ();
        stdout.printf ("label=%s, keyword=%s\n", opt.label, opt.keyword);

stdout.printf ("db=%s, user=%s, passwd=%s, host=%s, port=%s, tty=%s, options=%s\n", conn.get_db (), conn.get_user (), conn.get_passwd (), conn.get_host (), conn.get_port (), conn.get_tty (), conn.get_options ());

        /* close the portal ... we don't bother to check for errors ... */
        res = conn.exec ("CLOSE myportal");

        /* end the transaction */
        res = conn.exec ("END");

        return 0;
}

但是每當我跑步時

$ valac --pkg libpq test.vala -X -lpq

在 mingw cmd 行中我得到

C:/.../test.vala.c:7:10: fatal error: postgresql/libpq-fe.h: No such file or directory
    7 | #include <postgresql/libpq-fe.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Compilation failed: 1 error(s), 0 warning(s)
error: cc exited with status 1

我一直在嘗試很多方法來使用pacman -S安裝 postgres，包括

 pacman -S mingw-w64-x86_64-postgresql 

和許多其他版本的 libpq

Answer 1

該錯誤來自 C 編譯器 ( cc )，它說它找不到使用的 C 頭文件。 首先要嘗試的是安裝頭文件，對於 Arch Linux（使用pacman ），我相信libpq-fe.h頭文件在postgresql-devel包中。