c - 使用 rpcgen 的简单计算器

Question

我是 C 语言编程的新手。我尝试创建一个小而简单的程序来将文件 calculs.x 中的两个整数相加

这里是calculs.x文件的内容

/* calculs.x*/

struct data_in {
    int arg1;
    int arg2;
};
typedef struct data_in data_in;

struct result_int {
    int result;
    int errno;
};

struct result_float {
    int result;
    int errno;
};

typedef struct result_int result_int;
typedef struct result_float result_float;

program CALCULS{
    version VERSION_UN{
        void CALCULS_NULL(void) = 0;
        result_int ADD (data_in) = 1;
        result_int SUB(data_in) = 2;
        result_int MUL(data_in) = 3;
        result_float DIV (data_in) = 4;
    } = 1;
} = 0x20000001;

我第一次为客户创建了一个文件calculs.c:

#include <rpc/rpc.h>
#include "calculs.h"

int main(int argc, char *argv[]) {
    int buffer[256];
    struct data_in input;
    struct result_int *output;
    CLIENT *cl;

    if (argc != 2) {
        printf("usage: client hostname_of_server\n");
        exit(1);
    }

    /*Etablir le lien vers le serveur distant
     * cl = clnt_create(server, PROG, VERS, prot);
     */
    cl = clnt_create(argv[1], CALCULS, VERSION_UN, "tcp");
    if (cl == NULL) {
        clnt_pcreateerror(argv[1]);
        exit(1);
    }

    input.arg1 = 5;
    input.arg2 = 5;

    output = add_1(&input, cl);
    if (output == NULL) {
        clnt_perror(cl, argv[1]);
        exit(1);
    }
    printf("the result field is %d\n", output->result);
    printf("the errno field is %d\n", output->errno);

    clnt_destroy(cl);

    return 0;
}

我在编译这个文件时没有收到任何错误，但是对于另一个 rcalculs.c 文件，我无法编译。这是文件内容 rcalculs.c:

#include <rpc/rpc.h>
#include "calculs.h"

result_int *add_1(struct data_in data, struct svc_req *rqstp) {
    int buffer;
    struct result_int result;
    int a = data.arg1;
    int b = data.arg2;
    buffer = a+b;
    result.result = buffer;
    result.errno =0;
    return result;
}

编译报错是

rcalculs.c:11:13: erreur: conflicting types for ‘add_1’
In file included from rcalculs.c:9:0:
calculs.h:46:22: note: previous declaration of ‘add_1’ was here
rcalculs.c: In function ‘add_1’:
rcalculs.c:19:5: erreur: incompatible types when returning type ‘struct result_int’ but ‘struct result_int *’ was expected

你能帮我解决这个问题吗？

Answer 1

按如下方式使用您的 calculs.x。

/* calculs.x*/

struct data_in {
    int arg1;
    int arg2;
};
typedef struct data_in data_in;

struct result_int {
    int result;
    int errno;
};

struct result_float {
    int result;
    int errno;
};

typedef struct result_int result_int;
typedef struct result_float result_float;

program CALCULS{
    version VERSION_UN{
        void CALCULS_NULL(void) = 0;
        result_int ADD (data_in) = 1;
        result_int SUB(data_in) = 2;
        result_int MUL(data_in) = 3;
        result_float DIV (data_in) = 4;
    } = 1;
} = 0x20000001;

对于您的客户 calculs.c 用户

#include <rpc/rpc.h>
#include "calculs.h"

result_int *add_1(struct data_in data, struct svc_req *rqstp);

int main(int argc, char *argv[]) {
    int buffer[256];
    struct data_in input;
    struct result_int *output;
    CLIENT *cl;

    if (argc != 2) {
        printf("usage: client hostname_of_server\n");
        exit(1);
    }

    /*Etablir le lien vers le serveur distant
     * cl = clnt_create(server, PROG, VERS, prot);
     */
    cl = clnt_create(argv[1], CALCULS, VERSION_UN, "tcp");
    if (cl == NULL) {
        clnt_pcreateerror(argv[1]);
        exit(1);
    }

    input.arg1 = 5;
    input.arg2 = 5;

    output = add_1(&input, cl);
    if (output == NULL) {
        clnt_perror(cl, argv[1]);
        exit(1);
    }
    printf("the result field is %d\n", output->result);
    printf("the errno field is %d\n", output->errno);

    clnt_destroy(cl);

    return 0;
}

rcalculs.c 的内容:

#include <rpc/rpc.h>
#include "calculs.h"

result_int *add_1(struct data_in data, struct svc_req *rqstp) {
    int buffer;
    struct result_int result;
    int a = data.arg1;
    int b = data.arg2;
    buffer = a+b;
    result.result = buffer;
    result.errno =0;
    return &result;
}

让我知道它是否有效。