CODEWITHSUNDEEP
cgocgo
KiYugadgeter
KiYugadgeter

Reputation: 4014

Does not display printf result in cgo

When I ran this code, I expected to printing result like A: 4, B: 89. But actually, Does not display nothing.

Why this program does not display result to stdout?

main.go:

package main

/*
#include "c.h"

*/
import "C"

import (
    "unsafe"
)

type S struct {
    A int
    B int
}

func main() {
    s := &S{A: 4, B: 89}
    pass_to_c := (*C.S)(unsafe.Pointer(s))
    C.gostruct(pass_to_c)
}

c.h

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    long int A;
    long int B;
} S;

extern void gostruct(S *struct_s) {
    printf("A: %ld, B: %ld\n", struct_s->A, struct_s->B);
}

Upvotes: 2

Views: 2778

Answers (3)

duoduo
duoduo

Reputation: 71

Adding "console": "integratedTerminal" to the vscode launch.json solved my problem.

Upvotes: 2

yurenchen
yurenchen

Reputation: 2483

I run program in LiteIDE, not show c printf output.

But run the same program in terminal, then c printf output displayed.

Upvotes: 1

KiYugadgeter
KiYugadgeter

Reputation: 4014

Thanks for comments.

I can got expected result with below codes

main.go:

package main

/*
#include "c.h"

*/
import "C"

import (
    "unsafe"
)

type S struct {
    A int64 // 64bit int
    B int64 // 64bit int 
}

func main() {
    s := &S{A: 4, B: 89}
    pass_to_c := (*C.S)(unsafe.Pointer(s))
    C.gostruct(pass_to_c)
}

c.h:

#include <stdio.h>
#include <stdlib.h>

typedef struct {
    long long int A; // 64bit int
    long long int B; // 64bit int
} S;

extern void gostruct(S *struct_s) {
    printf("{A: %lld, B: %lld}\n", struct_s->A, struct_s->B);
}

I suppose struct field must use same type between languages. In question code, struct fields type are not same. (C struct: 32bit int, Go struct: 64bit int)

In answer code, struct field is same between language. (both struct: 64bit int)

Note that My architecture is darwin/amd64

Upvotes: 2

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