I'm getting an error "Use of undeclared identifier "BUFFER_LENGTH"". I've added the header in which "BUFFER_LENGTH" has been declared. I've shown the project structure below:
Project
|_ main.c
|_ application
|_ main_functionality.c
|_ headers
|_ socket.h
main.c
#include "application/main_functionality.c"
int main(int args, char *argv[]) {
my_main(argc, argv);
return 0;
}
main_functionality.c
#include "../headers/socket.h"
unsigned char inputBuffer [BUFFER_LENGTH]; <-- ERROR!!!
int my_main(int argc, char *argv[]) {
\\ code
return 0;
}
socket.h
#if defined __cplusplus
extern "C" {
#endif
#define BUFFER_LENGTH 256
#if defined __cpluscplus
}
#endif
socket.h contains the value for BUFFER_LENGTH and I've included the filename in main_functionality.c. I still get "Use of undeclared identifier" error.
Related
This is my main code:
#include "startup.h"
int main(int argc, char *argv[]) {
printBanner(); <-- Undefined symbol for x86_64
readParameters(argc, argv); <-- Undefined symbol for x86_64
}
Contents for startup.h:
#ifndef STARTUP_H
#define STARTUP_H
#if defined __cplusplus
extern "C" {
#endif
void printBanner(void);
void readParameters(const int argc, char *argv[]);
#if defined _cplusplus
}
#endif
#endif
The implementations of the above mentioned functions is in startup.c:
#include "startup.h"
void readParameters(const int argc, char *argv[]) {
// code
}
void printBanner() {
// code
}
All the 3 files are within the same folder. Is there anything that is missing in terms of settings? I'm using xcode for this project.
I'm calling a function that is defined in .h from my main and the header is included in the .c file where functions are implemented. Can't see anything wrong with it.
I try to build ipref3.dll for windows
I found How to compile iperf3 for Windows
Built it but i got only iperf3.exe and libiperf.a
I found, how create dll manual
gcc -s -shared -o iperf3.dll units.o timer.o tcp_window_size.o tcp_info.o net.o iperf_util.o iperf_sctp.o iperf_udp.o iperf_tcp.o iperf_server_api.o iperf_locale.o iperf_client_api.o iperf_error.o iperf_api.o cjson.o -Wl,--enable-auto-import,--export-all-symbols,--subsystem,windows
after i found how need to initialize
HMODULE h = LoadLibrary(TEXT("cygwin1.dll"));
PFN_CYGWIN_DLL_INIT init = (PFN_CYGWIN_DLL_INIT)GetProcAddress(h, "cygwin_dll_init");
init();
Now i can load dll and make initialization but when i start test iperf_run_client application is crashed
Unhandled exception at 0x611537C0 (cygwin1.dll) in iprerf-server.exe:
0xC0000005: Access violation reading location 0x00740000.
How can solve this problem?
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <WinSock2.h>
//#include <unistd.h>
#include <string.h>
//#include <sysexits.h>
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#include "iperf_api.h"
#ifdef WIN64
#pragma comment(lib, "iperf3_64.lib")
#else
#pragma comment(lib, "iperf3.lib")
#endif
#pragma comment(lib, "ws2_32.lib")
typedef void *register_frame();
typedef int *hello_f();
typedef int(*PFN_HELLO)();
typedef void(*PFN_CYGWIN_DLL_INIT)();
#pragma pack(push, 1)
int main(int argc, char** argv)
{
WSADATA wsaData;
int wsaErr = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (wsaErr != 0) {
printf("WSAStartup failed with error: %d\n", wsaErr);
return 1;
}
//PFN_HELLO fnHello;
HMODULE /*hLib, */h = LoadLibrary(TEXT("cygwin1.dll"));
PFN_CYGWIN_DLL_INIT init = (PFN_CYGWIN_DLL_INIT)GetProcAddress(h, "cygwin_dll_init");
init();
char* argv0;
char* host;
int port;
struct iperf_test *test;
argv0 = strrchr(argv[0], '/');
if (argv0 != (char*)0)
++argv0;
else
argv0 = argv[0];
if (argc != 3) {
fprintf(stderr, "usage: %s [host] [port]\n", argv0);
exit(EXIT_FAILURE);
}
host = argv[1];
port = atoi(argv[2]);
test = iperf_new_test();
if (test == NULL) {
fprintf(stderr, "%s: failed to create test\n", argv0);
exit(EXIT_FAILURE);
}
iperf_defaults(test);
iperf_set_verbose(test, 1);
iperf_set_test_role(test, 'c');
iperf_set_test_server_hostname(test, host);
iperf_set_test_server_port(test, port);
/* iperf_set_test_reverse( test, 1 ); */
iperf_set_test_omit(test, 3);
iperf_set_test_duration(test, 5);
iperf_set_test_reporter_interval(test, 1);
iperf_set_test_stats_interval(test, 1);
/* iperf_set_test_json_output( test, 1 ); */
if (iperf_run_client(test) < 0) {
fprintf(stderr, "%s: error - %s\n", argv0, iperf_strerror(i_errno));
exit(EXIT_FAILURE);
}
if (iperf_get_test_json_output_string(test)) {
fprintf(iperf_get_test_outfile(test), "%zd bytes of JSON emitted\n",
strlen(iperf_get_test_json_output_string(test)));
}
iperf_free_test(test);
exit(EXIT_SUCCESS);
}
The reason why the shared lib is not built is:
libtool: warning: undefined symbols not allowed in x86_64-unknown-cygwin
shared libraries; building static only
the easy way to bypass it, in a clean build is to use:
$ make libiperf_la_LIBADD="-no-undefined"
The build will include the shared libray and the import library
$ find . -name "*dll*"
./src/.libs/cygiperf-0.dll
./src/.libs/libiperf.dll.a
For what I see to make a build on cygwin is also needed to remove a definition
in src/iperf_config.h after running configure
/* #define HAVE_SETPROCESSAFFINITYMASK 1 */
PS #1: iperf-2.0.5-1 is available as cygwin package
PS #2: your code is Windows-like while Cygwin is a Unix-like system, you can not mix them
I found solution
1) It need to create addition dll: my_crt0.dll
#include <sys/cygwin.h>
#include <stdlib.h>
typedef int (*MainFunc) (int argc, char *argv[], char **env);
void my_crt0 (MainFunc f)
{
cygwin_crt0(f);
}
gcc -c my_crt0.c
gcc -o my_crt0.dll my_crt0.o -s -shared -Wl,--subsystem,windows,--enable-auto-import,--export-all-symbols,--out-implib,my_crt0.lib
2) Modify main code
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <WinSock2.h>
#include <string.h>
#include "iperf_api.h"
#pragma comment(lib, "iperf3.lib")
#pragma comment(lib, "ws2_32.lib")
typedef int(*MainFunc) (int argc, char *argv[], char **env);
typedef void(*my_crt0)(MainFunc f);
int main2(int argc, char** argv, char **env)
{
char* argv0;
char* host;
int port;
struct iperf_test *test;
host = (char*)"127.0.0.1";
port = 4000;
test = iperf_new_test();
if (test == NULL) {
exit(EXIT_FAILURE);
}
iperf_defaults(test);
iperf_set_verbose(test, 1);
iperf_set_test_role(test, 'c');
iperf_set_test_server_hostname(test, host);
iperf_set_test_server_port(test, port);
/* iperf_set_test_reverse( test, 1 ); */
iperf_set_test_omit(test, 3);
iperf_set_test_duration(test, 5);
iperf_set_test_reporter_interval(test, 1);
iperf_set_test_stats_interval(test, 1);
/* iperf_set_test_json_output( test, 1 ); */
iperf_strerror(0);
if (iperf_run_client(test) < 0) {
fprintf(stderr, "%s: error - %s\n", argv0, iperf_strerror(i_errno));
exit(EXIT_FAILURE);
}
if (iperf_get_test_json_output_string(test)) {
fprintf(iperf_get_test_outfile(test), "%zd bytes of JSON emitted\n",
strlen(iperf_get_test_json_output_string(test)));
}
iperf_free_test(test);
exit(EXIT_SUCCESS);
return 1;
}
int main(int argc, char** argv)
{
WSADATA wsaData;
int wsaErr = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (wsaErr != 0) {
printf("WSAStartup failed with error: %d\n", wsaErr);
return 1;
}
{
HMODULE /*hLib, */h = LoadLibrary(TEXT("my_crt0.dll"));
my_crt0 init = (my_crt0)GetProcAddress(h, "my_crt0");
init(main2);
}
exit(EXIT_SUCCESS);
}
Now it compiled and worked to VS 2015
Here is my code:
helloworld.go:
package main
import "C"
import "unsafe"
//export HelloWorld
func HelloWorld() *C.char {
cs := C.CString("Hello World!")
C.free(unsafe.Pointer(cs))
return cs
}
func main() {}
One of the errors I got:
src/helloworld.go:9:2: could not determine kind of name for C.free
Based on this article: https://blog.golang.org/c-go-cgo
I also found out that I need to add #include <stdlib.h> at top of my C file.
helloworld.h:
#include <stdlib.h>
/* Created by "go tool cgo" - DO NOT EDIT. */
/* package command-line-arguments */
/* Start of preamble from import "C" comments. */
/* End of preamble from import "C" comments. */
/* Start of boilerplate cgo prologue. */
#line 1 "cgo-gcc-export-header-prolog"
#ifndef GO_CGO_PROLOGUE_H
#define GO_CGO_PROLOGUE_H
typedef signed char GoInt8;
typedef unsigned char GoUint8;
typedef short GoInt16;
typedef unsigned short GoUint16;
typedef int GoInt32;
typedef unsigned int GoUint32;
typedef long long GoInt64;
typedef unsigned long long GoUint64;
typedef GoInt64 GoInt;
typedef GoUint64 GoUint;
typedef __SIZE_TYPE__ GoUintptr;
typedef float GoFloat32;
typedef double GoFloat64;
typedef float _Complex GoComplex64;
typedef double _Complex GoComplex128;
/*
static assertion to make sure the file is being used on architecture
at least with matching size of GoInt.
*/
typedef char _check_for_64_bit_pointer_matching_GoInt[sizeof(void*)==64/8 ? 1:-1];
typedef struct { const char *p; GoInt n; } GoString;
typedef void *GoMap;
typedef void *GoChan;
typedef struct { void *t; void *v; } GoInterface;
typedef struct { void *data; GoInt len; GoInt cap; } GoSlice;
#endif
/* End of boilerplate cgo prologue. */
#ifdef __cplusplus
extern "C" {
#endif
extern char* HelloWorld();
#ifdef __cplusplus
}
#endif
I tried it to no success.
I need to free the memory.
How do I do this? Because in there example it prints out the string. I want to return it. Without C.free. I am able to do it. I am just worried of causing a memory leak or some other issue.
Command cgo
// Go string to C string
// The C string is allocated in the C heap using malloc.
// It is the caller's responsibility to arrange for it to be
// freed, such as by calling C.free (be sure to include stdlib.h
// if C.free is needed).
func C.CString(string) *C.char
If the import of "C" is immediately preceded by a comment, that
comment, called the preamble, is used as a header when compiling the C
parts of the package.
For example,
package main
/*
#include <stdlib.h>
*/
import "C"
import "unsafe"
//export HelloWorld
func HelloWorld() *C.char {
cs := C.CString("Hello World!")
C.free(unsafe.Pointer(cs))
return cs
}
func main() {}
I have been trying to build a device adapter for a open-source software called Micro-manager to control a microscope and there are some problems that I am facing, there are these two files (one header and the other CPP) that are already present in the open source package of Micro-Manager.
//MoudluleInterface.h
#ifndef _MODULE_INTERFACE_H_
#define _MODULE_INTERFACE_H_
#ifdef WIN32
#ifdef MODULE_EXPORTS
#define MODULE_API __declspec(dllexport)
#else
#define MODULE_API __declspec(dllimport)
#endif
#else
#define MODULE_API
#endif
#define MM_MODULE_ERR_OK 1000
#define MM_MODULE_ERR_WRONG_INDEX 1001
#define MM_MODULE_ERR_BUFFER_TOO_SMALL 1002
///////////////////////////////////////////////////////////////////////////////
// header version
// NOTE: If any of the exported module API calls changes, the interface version
// must be incremented
// new version 5 supports device discoverability
#define MODULE_INTERFACE_VERSION 7
#ifdef WIN32
const char* const LIB_NAME_PREFIX = "mmgr_dal_";
#else
const char* const LIB_NAME_PREFIX = "libmmgr_dal_";
#endif
#include "MMDevice.h"
///////////////////////////////////////////////////////////////////////////////
// Exported module interface
///////////////////////////////////////////////////////////////////////////////
extern "C" {
MODULE_API MM::Device* CreateDevice(const char* name);
MODULE_API void DeleteDevice(MM::Device* pDevice);
MODULE_API long GetModuleVersion();
MODULE_API long GetDeviceInterfaceVersion();
MODULE_API unsigned GetNumberOfDevices();
MODULE_API bool GetDeviceName(unsigned deviceIndex, char* name, unsigned bufferLength);
MODULE_API bool GetDeviceDescription(const char* deviceName, char* name, unsigned bufferLength);
And here is a part of the CPP file which defines these functions
//ModuleInterface.cpp
#define _CRT_SECURE_NO_DEPRECATE
#include "ModuleInterface.h"
#include <vector>
#include <string>
typedef std::pair<std::string, std::string> DeviceInfo;
std::vector<DeviceInfo> g_availableDevices;
int FindDeviceIndex(const char* deviceName)
{
for (unsigned i=0; i<g_availableDevices.size(); i++)
if (g_availableDevices[i].first.compare(deviceName) == 0)
return i;
return -1;
}
MODULE_API long GetModuleVersion()
{
return MODULE_INTERFACE_VERSION;
}
MODULE_API long GetDeviceInterfaceVersion()
{
return DEVICE_INTERFACE_VERSION;
}
MODULE_API unsigned GetNumberOfDevices()
{
return (unsigned) g_availableDevices.size();
}
MODULE_API bool GetDeviceName(unsigned deviceIndex, char* name, unsigned bufLen)
{
if (deviceIndex >= g_availableDevices.size())
return false;
Now the problem is it gives me an error C2491 (definition of dllimport function not allowed)
I did research about this and it usually is when a function is defined when it is supposed to be declared, I have already defined the function in ModuleInterface.h and then used it in ModuleInterface.cpp but it still shows the same error.
Can there be some other possibility for this error to occur? Or is there something wrong with the code?
You're not supposed to repeat your MODULE_API declaration in the definition, having it as part of the declaration is good enough. Remove the use of MODULE_API from the .cpp file and the code should compile.
I want to create a file under a /proc/driver directory. I would like to use a macro like proc_root_driver (or something else provided) rather than use "driver/MODULE_NAME" explicitly. I use create_proc_entry :
struct proc_dir_entry *simpleproc_fops_entry;
simpleproc_fops_entry = create_proc_entry(MODULE_NAME, 0400, NULL /* proc_root_dir */);
After googling, I found suggestion to use proc_root_driver, but when I use it, I get the error
proc_root_driver undeclared in this function
And also, proc_root_driver is not available in linux/proc_fs.h.
I have tried to declare structure like this:
struct proc_dir_entry proc_root;
struct proc_dir_entry *proc_root_driver = &proc_root;
The compilation errors gone, but the file didn't appear under /proc/driver or /proc. How can I make create an entry in /proc?
Looking at proc_fs.h, proc_root_driver is defined as :
extern struct proc_dir_entry *proc_root_driver;
so long as CONFIG_PROC_FS is enabled. If you have CONFIG_PROC_FS selected when you configure your kernel, you should be able to use it as you suggested yourself i.e. :
#include <linux/proc_fs.h>
struct proc_dir_entry * procfile
procfile = create_proc_entry("myprocfile", 0400, proc_root_driver);
If this does not work, check that you have CONFIG_PROC_FS set. To make sure, you can compile your source file with the -E option and check that the create_proc_entry call includes a non NULL parameter as the last parameter. If it is NULL, or the call is not there at all, then CONFIG_PROC_FS is not enabled.
/* proc entries for ayyaz */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/err.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#ifdef CONFIG_PROC_FS
/*====================================================================*/
/* Support for /proc/ayyaz */
static struct proc_dir_entry *proc_ayyaz;
DEFINE_MUTEX(ayyaz_table_mutex);
/*====================================================================*/
/* Init code */
static int ayyaz_read_proc (char *page, char **start, off_t off, int count,
int *eof, void *data_unused)
{
int len, l, i;
off_t begin = 0;
mutex_lock(&ayyaz_table_mutex);
len = sprintf(page, "hello ayyaz here\n");
mutex_unlock(&ayyaz_table_mutex);
if (off >= len+begin)
return 0;
*start = page + (off-begin);
return ((count < begin+len-off) ? count : begin+len-off);
}
static int __init init_ayyaz(void)
{
if ((proc_ayyaz = create_proc_entry( "ayyaz_maps", 0, NULL )))
proc_ayyaz->read_proc = ayyaz_read_proc;
return 0;
}
static void __exit cleanup_ayyaz(void)
{
if (proc_ayyaz)
remove_proc_entry( "ayyaz", NULL);
}
module_init(init_ayyaz);
module_exit(cleanup_ayyaz);
#else
#error "Please add CONFIG_PROC_FS=y in your .config "
#endif /* CONFIG_PROC_FS */
MODULE_LICENSE("proprietary");
MODULE_AUTHOR("Md.Ayyaz A Mulla <md.ayyaz#gmail.com>");
MODULE_DESCRIPTION("proc files for ayyaz");
Compile this driver. If it compiles sucessfully, then you will see /proc/ayyaz.
#define PROC_ENTRY_NAME "driver/XX"
static struct proc_dir_entry *proc_XX;
static int XX_read_proc (char *page, char **start, off_t off, int count,
int *eof, void *data_unused)
{
return 0;
}
static int XX_write_proc (struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
return 0;
}
static int __init XX_add_driver(void)
{
if ((proc_flash = XX_entry(PROC_ENTRY_NAME, 0, NULL))) {
proc_XX->read_proc = XX_read_proc;
proc_XX->write_proc = XX_write_proc;
}
...
}
static void __exit XX_remove(void)
{
if (proc_flash)
remove_proc_entry(PROC_ENTRY_NAME, NULL);
return;
}
Then you can find the /proc/driver/XX entry.