Callback TypeError: error setting return value - value is out of bounds

[mojo3344]

I'm new to node-ffi, and have been learning how to use callbacks, so this may be an understanding issue. But, I'm getting an odd error after a callback works with this test case:

var ffi = require('ffi')
var ref = require('ref')

// Interface into the native lib
var libLM = ffi.Library('./LMNodeLib', {
  'Object_new': [ "pointer", [] ],
  'Object_init': [ "void", [ "pointer" ] ],
  'Object_test': [ "int", [ "pointer", "pointer"] ],
  'Object_getDataByte': [ "int", [ "pointer", "int"] ]
})


// Callback from the native lib back into js
var callback = ffi.Callback('int', ['void *', 'int', 'string', 'string'], 
                            function (theObj, someInt, someStr1, someStr2) {  

    // access some values
    console.log("SomeInt: ", someInt)
    console.log("SomeStr1: ", someStr1)
    console.log("SomeStr2: ", someStr2)

    // Access the byte array in the object via a callback
    var i = 0
    while (i < 128) {
        if (libLM.Object_getDataByte(theObj,i) != i) {
            console.log("fail in callback")
        }

        i += 1
    }

    console.log("callback worked")
})

// make an extra reference to callback to avoid GC.
process.on('exit', function() {
    callback
});

var testObj = libLM.Object_new()
libLM.Object_init(testObj)
console.log("calling test")
libLM.Object_test(testObj, callback)
console.log('All done')

Here's my native lib:

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

typedef struct {

    int state;
    unsigned char buf[128];

} Object_t, *Object_p;


void* Object_new() {
    void* obj = malloc(sizeof(Object_t));
    return obj;
}

void Object_init(Object_p self) {

    self->state = 5;
    int i = 0;
    while (i < 128) {
        self->buf[i] = i;
        i += 1;
    }
    printf("Object_init done\n");
}

typedef int (*callbackFP_t)(void* theObj, int theInt, char* theStr1, char* theStr2);
int Object_test(Object_p self, callbackFP_t fp) {

    unsigned char* dataPtr = (unsigned char*) self;

    int i = 0;
    while (i < 128) {

        if (self->buf[i] != i)
        {
            printf("FAIL\n");
            return 0;
        }
        i += 1;
    }

    // hit the callback
    printf("Hitting the callback\n");
    char buf1[256];
    strcpy(buf1, "the first string");
    (*fp)( (void*) self, 8, buf1, "second string");

    return 1;
}


int Object_getDataByte(Object_p self, int i) {
    return self->buf[i];
}

Which I compile with:
gcc -dynamiclib -undefined suppress -flat_namespace -g LMNodeLib.c -o LMNodeLib.dylib

It produces this output:

Object_init done
calling test
Hitting the callback
SomeInt:  8
SomeStr1:  the first string
SomeStr2:  second string
callback worked

/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/lib/_foreign_function.js:59
    bindings.ffi_call(cif, funcPtr, result, argsList)
             ^
TypeError: error setting return value - value is out of bounds
    at TypeError (<anonymous>)
    at checkInt (buffer.js:781:11)
    at SlowBuffer.Buffer.writeInt32LE (buffer.js:913:5)
    at Object.set (/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/node_modules/ref/lib/ref.js:920:52)
    at Object.set (/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/node_modules/ref/lib/ref.js:479:10)
    at /Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/lib/callback.js:54:11
    at Object.ForeignFunction.proxy [as Object_test] (/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/lib/_foreign_function.js:59:14)
    at Object.<anonymous> (/Users/morgan/shared/mojolabs/projects/js/node/node-ffi/testCB/LMNodeLib.js:53:7)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)

Ie, the callback works, but the "all done" print never happens. For the record, I'm on OS X, node v0.10.0, and using ffi from npm, 1.2.5.

Not sure if this is a callback understanding issue on my part or a bug.

Any ideas?

[TooTallNate]

Change the ffi.Callback return value to "void" instead of "int".

On Friday, April 19, 2013, Morgan Jones wrote:

I'm new to node-ffi, and have been learning how to use callbacks, so this
may be an understanding issue. But, I'm getting an odd error after a
callback works with this test case:

var ffi = require('ffi')
var ref = require('ref')

// Interface into the native lib
var libLM = ffi.Library('./LMNodeLib', {
'Object_new': [ "pointer", [] ],
'Object_init': [ "void", [ "pointer" ] ],
'Object_test': [ "int", [ "pointer", "pointer"] ],
'Object_getDataByte': [ "int", [ "pointer", "int"] ]
})

// Callback from the native lib back into js
var callback = ffi.Callback('int', ['void *', 'int', 'string', 'string'],
function (theObj, someInt, someStr1, someStr2) {

// access some values
console.log("SomeInt: ", someInt)
console.log("SomeStr1: ", someStr1)
console.log("SomeStr2: ", someStr2)

// Access the byte array in the object via a callback
var i = 0
while (i < 128) {
    if (libLM.Object_getDataByte(theObj,i) != i) {
        console.log("fail in callback")
    }

    i += 1
}

console.log("callback worked")

})

// make an extra reference to callback to avoid GC.
process.on('exit', function() {
callback
});

var testObj = libLM.Object_new()
libLM.Object_init(testObj)
console.log("calling test")
libLM.Object_test(testObj, callback)
console.log('All done')

Here's my native lib:

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

typedef struct {

int state;
unsigned char buf[128];

} Object_t, *Object_p;

void* Object_new() {
void* obj = malloc(sizeof(Object_t));
return obj;
}

void Object_init(Object_p self) {

self->state = 5;
int i = 0;
while (i < 128) {
    self->buf[i] = i;
    i += 1;
}
printf("Object_init done\n");

}

typedef int (callbackFP_t)(void theObj, int theInt, char* theStr1, char* theStr2);
int Object_test(Object_p self, callbackFP_t fp) {

unsigned char* dataPtr = (unsigned char*) self;

int i = 0;
while (i < 128) {

    if (self->buf[i] != i)
    {
        printf("FAIL\n");
        return 0;
    }
    i += 1;
}

// hit the callback
printf("Hitting the callback\n");
char buf1[256];
strcpy(buf1, "the first string");
(*fp)( (void*) self, 8, buf1, "second string");

return 1;

}

int Object_getDataByte(Object_p self, int i) {
return self->buf[i];
}

Which I compile with:
gcc -dynamiclib -undefined suppress -flat_namespace -g LMNodeLib.c -o
LMNodeLib.dylib

It produces this output:

Object_init done
calling test
Hitting the callback
SomeInt: 8
SomeStr1: the first string
SomeStr2: second string
callback worked

/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/lib/_foreign_function.js:59
bindings.ffi_call(cif, funcPtr, result, argsList)
^
TypeError: error setting return value - value is out of bounds
at TypeError ()
at checkInt (buffer.js:781:11)
at SlowBuffer.Buffer.writeInt32LE (buffer.js:913:5)
at Object.set (/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/node_modules/ref/lib/ref.js:920:52)
at Object.set (/Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/node_modules/ref/lib/ref.js:479:10)
at /Users/morgan/shared/mojolabs/projects/js/node/node_modules/ffi/lib/callback.js:54:11
at Object.ForeignFunction.proxy as Object_test
at Object. (/Users/morgan/shared/mojolabs/projects/js/node/node-ffi/testCB/LMNodeLib.js:53:7)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)

Ie, the callback works, but the "all done" print never happens. For the
record, I'm on OS X, node v0.10.0, and using ffi from npm, 1.2.5.

Not sure if this is a callback understanding issue on my part or a bug.

Any ideas?

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/121
.

[mojo3344]

That worked! I also tried adding a "return 1" to the end of the callback, and that also worked.

Thanks very much for spotting that.