I have found a lot of questions with this error (initializer element is not constant) but I don't know how to adapt the answers in my code.
(I'm new in C)
I have an error with this part:
#include <mach/i2c.h>
#include <mach/irqs-sun7i.h>
/*
* /////////// from mach/i2c.h //////////
struct sun7i_i2c_platform_data {
int bus_num;
unsigned int frequency;
};
*/
static struct sun7i_i2c_platform_data sun7i_i2c_platform_data = {
.bus_num = 1,
.frequency = 100*1000,
};
static struct mpu_platform_data gyro_platform_data = {
.int_config = 0x10,
.level_shifter = 0,
.orientation = { -1, 0, 0,
0, 1, 0,
0, 0, -1 },
.sec_slave_type = SECONDARY_SLAVE_TYPE_COMPASS,
.sec_slave_id = COMPASS_ID_AK8972,
.secondary_i2c_addr = 0x0E
};
/*
* /////////// from mach/i2c.h //////////
*
* struct i2c_board_info {
char type[I2C_NAME_SIZE];
unsigned short flags;
unsigned short addr;
void *platform_data;
struct dev_archdata *archdata;
struct device_node *of_node;
int irq;
};*/
static struct i2c_board_info __initdata sun7i_i2c_platform_device[] = {
{
I2C_BOARD_INFO("mpu6050", 0x68),
.platform_data = &gyro_platform_data,
.archdata = sun7i_i2c_platform_data,
},
};
/*
// ORIGINAL //
static struct i2c_board_info __initdata single_chip_board_info[] = {
{
I2C_BOARD_INFO("mpu6050", 0x68),
.irq = (IH_GPIO_BASE + MPUIRQ_GPIO),
.platform_data = &gyro_platform_data,
},
};
*/
static void __init sun7i_i2c_init(void)
{
i2c_register_board_info(2, sun7i_i2c_platform_device,
ARRAY_SIZE(sun7i_i2c_platform_device));
}
My problem come from .archdata init:
c:160:17: error: initializer element is not constant
I have tried with
.archdata = &sun7i_i2c_platform_data,
but in this case I have a warning and the line is ignored:
warning: initialization from incompatible pointer type [enabled by default]
So, how to call properly my fonction ?
Thanks
Related
I am working on C Structures. I want to #define the struct values as follows.
// #define get_x() { .y = { .z = 1, .c = "test" } }; // this is working
// But I want to replace the above line with
#define get_y() { .z = 1, .c = "test" };
#define get_x() { .y = get_y() }; // this gives error
struct :
typedef struct {
int z;
char c[10];
} y_t;
typedef struct {
y_t y;
} x_t;
int main()
{
x_t x = get_x();
printf("c: %s", x.y.c);
return 0;
}
Will you please help me know, How can I do that?
Remove the ;, there is no ; in initialization. Typically, macros are in upper case.
#define GET_Y() { .z = 1, .c = "test" }
#define GET_X() { .y = GET_Y() }
I have two structures (one_d and two_d).
I have a function that will take struct two_d *smg as input. In main(), I am trying to create such smg so it will return value c increased.
My problem is that, while creating an array of struct two_d smg[2], I am not sure how to put inside information about its values, as it is a pointer to a different struct.
So how do you use pointer to a struct inside a struct? I would like to create struct two_d smg[2] but i dont now how to deal with struct one_d *a field in it
#include <stdio.h>
enum sid
{
DRB,
DRA,
};
struct one_d
{
unsigned int r;
unsigned int *p;
};
struct two_d
{
struct one_d *a;
enum sid z;
};
unsigned int getSmg(struct two_d *smg)
{
unsigned int c = 0;
const struct two_d *sd = NULL;
const struct one_d *ed = NULL;
for (sd = smg; sd->a != NULL; ++sd)
{
for (ed = sd->a; ed->p != NULL; ++ed)
{
if (DRA == sd->z)
{
/*P Increment the clear-state buffer size */
c += 1 + ed->r;
}
}
}
return c;
}
int main(void)
{
unsigned int rVal = 0;
struct two_d smg[2]={
//
// [0].a ={1,0},
// [0].z =DRA,
// [1].a={1,0},
// [1].z =DRA,
};
rVal = getSmg(smg);
printf("Return value is a %d\n", rVal);
printf("Return value is a l");
return( 0 );
}
Well, at least this compiles... I'm not game to run it, though...
For what it's worth...
enum sid { DRB, DRA, DRAwhoCares };
typedef struct {
unsigned int r;
unsigned int *p;
} oneD_t;
typedef struct {
oneD_t *a;
enum sid z;
} twoD_t;
unsigned int getSmg( twoD_t *smg ) {
unsigned int c = 0;
for( twoD_t *sd = smg; sd->a != NULL; +sd++ ) {
for( oneD_t *ed = sd->a; ed->p != NULL; ed++ ) {
if( DRA == sd->z ) {
/*P Increment the clear-state buffer size */
c += 1 + ed->r;
}
}
}
return c;
}
int main( void ) {
oneD_t foo[] = { { 1, NULL }, /* ... */ };
oneD_t bar[] = { { 1, NULL }, /* ... */ };
twoD_t smg[]={
{ foo, DRA, },
{ bar, DRA, },
{ NULL, DRAwhoCares, },
};
unsigned int rVal = getSmg( smg );
printf( "Return value: %u\n", rVal );
return 0; // return is not a function call... No parenthesis...
}
At rewriting kernel driver I got this warning:
msm-cirrus-playback.c:545:2: warning: braces around scalar initializer
Read that this warning appears when I am declaring one structure's field in {}:
struct random_struct test = {
{ .name = "StackOverflow" },
{ .name = "StackExchange" },
};
But my structure have 2-3 fields in {}:
static struct device_attribute *opalum_dev_attr = {
{
.attr->name = "temp-acc",
.show = opsl_temp_acc_show,
.store = opsl_temp_acc_store,
},
{
.attr->name = "count",
.show = opsl_count_show,
.store = opsl_count_store,
},
{
.attr->name = "ambient",
.show = opsl_ambient_show,
.store = opsl_ambient_store,
},
{
.attr->name = "f0",
.show = opsl_f0_show,
.store = opsl_f0_store,
},
{
.attr->name = "pass",
.show = opsl_pass_show,
},
{
.attr->name = "start",
.show = opsl_cali_start,
},
};
This structure:
struct device_attribute {
struct attribute attr;
ssize_t (*show)(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t (*store)(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
};
How can I fix this warning? Qualcomm kernels are building with -Werror flag, so this warning is critical.
static struct device_attribute *opalum_dev_attr means declare opalum_dev_attr as static pointer to struct device_attribute
Your code is trying to initialize a static array of struct device_attribute
What you want is: static struct device_attribute opalum_dev_attr[] which means declare opalum_dev_attr as static array of struct device_attribute
It is because you initialize the pointer to the struct not the struct itself.
you need to assign the reference to the struct for example by using compound literals
struct x
{
int a,b,c;
}a = {1,2,3};
void foo()
{
struct x a = {1,2,3};
struct x *b = {1,2,3}; // wrong warning here
struct x *x = &(struct x){1,2,3}; // correct reference to the struct assigned (using compound literal
struct x *y = (struct x[]){{1,2,3}, {4,5,6}, {4,5,6}, };
struct x z[] = {{1,2,3}, {4,5,6}, {4,5,6}, };
}
How can I set a user custom pointer in libwebsockets callback?
I added a pointer variable into a lws_protocol.
When callback function is called, user pointer is always NULL.
I use libwebsockets v3.0.
static int interrupted, rx_seen, test;
int ws_callback(struct lws *ws, enum lws_callback_reasons reason, void *user, void *in, size_t len) {
// user is NULL
return lws_callback_http_dummy(ws, reason, user, in, len);
}
int main() {
struct lws *ws;
struct lws_context_creation_info context_info;
struct lws_client_connect_info client_info;
struct lws_context *context;
struct lws_protocols protocols[] = {
{ "ws_callback", ws_callback, 0, 0, 0, POINTER_VARIABLE /* HERE */, 0 }
};
int n = 0;
// context creation info
memset(&context_info, 0, sizeof(context_info));
context_info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
context_info.port = CONTEXT_PORT_NO_LISTEN;
context_info.protocols = protocols;
context = lws_create_context(&context_info);
if (!context) {
return;
}
memset(&client_info, 0, sizeof(client_info));
client_info.context = context;
client_info.port = 8080;
client_info.address = "192.168.1.1";
client_info.path = "/";
client_info.host = client_info.address;
client_info.origin = client_info.address;
client_info.protocol = protocols[0].name;
client_info.pwsi = &ws;
lws_client_connect_via_info(&client_info);
while (n >= 0 && ws && !interrupted) {
n = lws_service(context, 1000);
}
lws_context_destroy(context);
return 0;
}
You must specify the size of per session data structure, but not the pointer itself. Per session data will be different for each connection.
typedef struct per_session_data {
void *user_space;
} per_session_data;
int ws_callback(struct lws *ws, enum lws_callback_reasons reason, void *user, void *in, size_t len)
{
/* This will be different for every connected peer */
per_session_data *data = (per_session_data*)user;
}
struct lws_protocols protocols[] = {
{ "ws_callback", ws_callback, sizeof(per_session_data), 0 }
{ NULL, NULL, 0, 0 } /* terminator */
};
You can also set optional user pointer that will be associated with the context. lws_context_creation_info has user variable for userspace. You must set it before creating the context
typedef struct per_session_data {
void *user_space;
/*
Same other variables
*/
} per_session_data;
int ws_callback(struct lws *ws, enum lws_callback_reasons reason, void *user, void *in, size_t len)
{
/* This will be different for every connected peer */
per_session_data *data = (per_session_data*)user;
/* This will be same for every connected peer */
void *userdata = lws_context_user(lws_get_context(ws));
/* userdata is POINTER_VARIABLE specified before context creating */
switch (reason)
{
case LWS_CALLBACK_ESTABLISHED:
/* Initialize per session data here */
break;
case LWS_CALLBACK_CLOSED:
/* Destroy per session data here */;
break;
default:
break;
}
}
struct lws_protocols protocols[] = {
{ "ws_callback", ws_callback, sizeof(per_session_data), 0 }
{ NULL, NULL, 0, 0 } /* terminator */
};
int main()
{
/*
your code here
*/
// context creation info
memset(&context_info, 0, sizeof(context_info));
context_info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
context_info.port = CONTEXT_PORT_NO_LISTEN;
context_info.protocols = protocols;
context_info.user = POINTER_VARIABLE; /* HERE */
context = lws_create_context(&context_info);
if (!context) {
return;
}
/*
your code here
*/
}
The following code gives me this warning:
tag_info.h:17: warning: missing braces around initializer
tag_info.h:17: warning: (near initialization for âtag_list_data[0].subtagsâ)
I have tried alot of things but nothing seems to be working. Can anyone please suggest something
typedef struct Attr{
char attr_name[64];
value_type_t value;
int mandatory;
}Attr_t;
typedef struct Tags {
unsigned int tag_id;
Attr_t *attr_list;
char *tag_name;
int tag_type;
int subtags[html_subtag_num];
}Tags_t;
Tags_t tag_list_data[150] = {
#include "tag_info.h"
{0,0,0,0,0}
};
where the "tag_info.h" contains :
#if defined(TAG_DEFINE)
#undef TAG_DEFINE
#else
#define TAG_DEFINE(a,b,c,...) {.tag_id=a, .tag_name=#b, .tag_type=c, ##__VA_ARGS__}
#endif
TAG_DEFINE(0,TAG_NONE,0,0),
TAG_DEFINE(1,!--,0,0),
TAG_DEFINE(2,!doctype,0,0),
TAG_DEFINE(3,a, 1, 1, 117, 59,11,118,92,100),
You are initializing subtags as if it were multiple members of the Tags struct:
typedef struct Tags {
...
int subtags_0;
int subtags_1;
int subtags_2;
} Tags_t;
Tags_t t = { ..., 0, 1, 2 };
But it is an array. Thus you should initialize it as a single entity.
typedef struct Tags {
...
int subtags[html_subtag_num];
} Tags_t;
Tags_t t = { .tag_id = 0, ..., { 0, 1, 2 } };
// or
Tags_t t = { .tag_id = 0, ..., .subtags = { 0, 1, 2 } };
Also, you don't need to use concatenation (##)
#define TAG_DEFINE(a,b,c,...) { ..., ## __VA_ARGS__}
In the end, it should look like
#define TAG_DEFINE(a,b,c,...) { ..., .subtags = { __VA_ARGS__ } }
...
Tags_t tag_list_data[150] = {
...
{ 0,0,0,0,{0}}
}
instead of
#define TAG_DEFINE(a,b,c,...) { ..., ##__VA_ARGS__}
...
Tags_t tag_list_data[150] = {
...
{ 0,0,0,0,0 }
}