I am having trouble using the curl_easy_escape function in a C++ dll. If I create a console application, curl_easy_escape works as expected.
cURL curl-7.28.1-devel-mingw32
Visual Studio 2010
Console Application (working as expected)
int _tmain(int argc, _TCHAR* argv[])
{
CURL *curl;
char *data1;
char *data2;
int data2len;
curl = curl_easy_init();
if (curl)
{
data1 = curl_easy_escape(curl, "this is a string with spaces", 0);
printf("\r\ndata1 = %s\r\n", data1);
data2 = curl_easy_unescape(curl, data1, 0, &data2len);
printf("\r\ndata2 = %s\r\n", data2);
curl_easy_cleanup(curl);
}
printf(“\r\nPress any key to continue\r\n”);
return 0;
Output
data1 = this%20is%20a%20string%20with%20spaces
data2 = this is a string with spaces
Press any key to continue
C++ DLL
Visual C++ > Win32 > Win32 Project
Application type = DLL (all other options as default)
Linker > Input > Additional Dependencies, added libcurl.lib
extern "C"
{
__declspec(dllexport) int * curl_test(char *sBuf)
{
CURL *curl;
curl = curl_easy_init();
if (curl)
{
// The following line does not work
//strcpy(sBuf, curl_easy_escape(curl, "this is a string with spaces", 0));
// This line does work
strcpy(sBuf, "this is a string with spaces");
curl_easy_cleanup(curl);
}
return 0;
}
}
The dll is used in a C program and calls curl_test with char ptr[256]. With curl_easy_escape in place, the LoadLibrary call fails:
Error: C interpreter run time error: Error -- File error : LoadLibrary(mydll.dll) failed : The specified procedure could not be found.
Note that this is on the LoadLibrary, so the curl_test function has not been called yet.
I suppose I can find some URL encode/decode functions, but would prefer to use what cURL already offers. I also have the same issue with the curl_easy_strerror function.
Could it be the ‘const char *’?
Update
Ideally I would like to use curl_easy_escape/curl_easy_unescape, but as a workaround I decided to implement my own URL encoding/decoding in C. I found efficient, well written encoding/decoding functions at http://www.geekhideout.com/urlcode.shtml
Related
According to https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/makepath-s-wmakepath-s?view=vs-2019#generic-text-routine-mappings _makepath_s should return an error code on failure.
On my system this is not true, it gives an assert (Expression: (L"Buffer is too small" && 0)) and then terminates the program. In release it simply terminates the program.
The only way I found to keep my program running is to set an empty invalid parameter handler:
void myInvalidParameterHandler(const wchar_t* expression,
const wchar_t* function,
const wchar_t* file,
unsigned int line,
uintptr_t pReserved)
{
}
_set_invalid_parameter_handler(myInvalidParameterHandler);
But this is not recommended. The docs say that this handler should abort the program.
And I also think that this modifies all secure function which is not what exactly what I want.
So is there a better way to get _makepath_s behave like the docs say?
TIA Michael
VS2017, MFC
Edit
A small sample:
char Path[_MAX_PATH];
char drive[_MAX_DRIVE] = "C:";
char dir[_MAX_DIR] = "Thisisaverylongdirname01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789";
char fname[_MAX_FNAME] = "Thisisaverylongfilename012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789";
char ext[_MAX_EXT] = "txt";
_makepath(Path, drive, dir, fname, ext);
I am trying to run sample rsa/dsa code using libtomcrypt.
I have installed LibTomMath first as make install, as a result following files are created.
/usr/lib/libtommath.a
/usr/include/tommath.h
After that I installed libtomcrypt with LibTomMath as external library
CFLAGS="-DLTM_DESC -DUSE_LTM -I/usr/include" EXTRALIBS="/usr/lib/libtommath.a " make install
As a result following file is created
/usr/lib/libtomcrypt.a
I am not getting any error while running following command
CFLAGS="-DLTM_DESC -DUSE_LTM -I/usr/include" EXTRALIBS="/usr/lib/libtommath.a " make test
I have gone through this document libtomcrypt_installation and libtomcrypt_resolved to successfully compile using
gcc -DLTM_DESC rsa_make_key_example.c -o rsa -ltomcrypt
or
gcc rsa_make_key_example.c -o rsa -ltomcrypt
no compile error. However when I try to run, I got following error.
./rsa
LTC_ARGCHK 'ltc_mp.name != NULL' failure on line 34 of file src/pk/rsa/rsa_make_key.c
Aborted
Here is my sample rsa code
#include <tomcrypt.h>
#include <stdio.h>
int main(void) {
# ifdef USE_LTM
ltc_mp = ltm_desc;
# elif defined (USE_TFM)
ltc_mp = tfm_desc;
# endif
rsa_key key;
int err;
register_prng(&sprng_desc);
if ((err = rsa_make_key(NULL, find_prng("sprng"), 1024/8, 65537,&key)) != CRYPT_OK) {
printf("make_key error: %s\n", error_to_string(err));
return -1;
}
/* use the key ... */
return 0;
}
Here is my sample dsa code
#include <tomcrypt.h>
#include <stdio.h>
int main(void) {
# ifdef USE_LTM
ltc_mp = ltm_desc;
# elif defined (USE_TFM)
ltc_mp = tfm_desc;
# endif
int err;
register_prng(&sprng_desc);
dsa_key key;
if ((err = dsa_make_key(NULL, find_prng("sprng"), 20, 128,&key)) != CRYPT_OK) {
printf("make_key error: %s\n", error_to_string(err));
return -1;
}
/* use the key ... */
return 0;
}
Here is how I have compiled it successfully,
gcc dsa_make_key_example.c -o dsa -ltomcrypt
When I try to run the code , I am getting following error .
./dsa
segmentation fault
EDIT 1:
I investigated further and found the reason for segmentation fault
#ifdef LTC_MPI
#include <stdarg.h>
int ltc_init_multi(void **a, ...)
{
...
...
if (mp_init(cur) != CRYPT_OK) ---> This line causes segmentation fault
Where am I making mistakes ? How to resolve this problem to run these programs successfully?
I am using linux , gcc. Any help/link will be highly appreciated. Thanks in advance.
It's been a year or so since this was asked, but I have some component of an answer, and a workaround.
The reason mp_init fails is that the "math_descriptor" is uninitialized. mp_init is a defined as
#define mp_init(a) ltc_mp.init(a)
where ltc_mp is a global struct (of type ltc_math_descriptor) that holds pointers to the math routines.
There are several implementations of the math routines available, and a user can choose which they want. For whatever reason, there does not seem to be a default math implementation chosen for certain builds of libtomcrypt. Thus, the init member of ltc_mp is null, and we get the SIGSEGV.
Here is a manual workaround:
You can make your desired ltc_math_descriptor struct available to your main() routine by #defineing one of
LTM_DESC -- built-in math lib
TFM_DESC -- an external fast math package
GMP_DESC -- presumably a GNU MultiPrecision implementation?
Before #include <tomcrypt.h> (or by using -D on the command-line).
Whichever you choose, a corresponding object will be declared:
extern const ltc_math_descriptor ltm_desc;
extern const ltc_math_descriptor tfm_desc;
extern const ltc_math_descriptor gmp_desc;
To use it, manually copy it to the global math descriptor:
E.g., in my case, for the local math imlpementation,
ltc_mp = ltm_desc;
Now libtomcrypt works.
I have following code:
int _tmain(int argc, char** argv) {
bool g_graphics = true;
palPhysics * pp = 0;
#ifndef PAL_STATIC
PF -> LoadPALfromDLL();
#endif
char a[] = "Bullet";
std::string aa;
aa = std::string(argv[1]);
//PF->SelectEngine("Bullet");
DebugBreak();
PF -> SelectEngine(argv[1]);
//PF->SelectEngine(aa);
//debug
// assert(false);
pp = PF -> CreatePhysics();
}
I am trying to read in the command line argument no. 1 in this line:
PF->SelectEngine(argv[1]);
However, I only get the first letter of the argument. I have also tried changing
int _tmain(int argc, char** argv)
to
int _tmain(int argc, TCHAR** argv), but then I get
error:
error C2664: 'palFactory::SelectEngine' : cannot convert parameter 1 from 'TCHAR *' to 'const PAL_STRING &'
PAL_STRING is just a std::string.
This might be a simple one, but I am not sure how to convert TCHAR to std::string, especially since TCHAR is something else depending on compiler /environment settings. Is anyone aware of an easy way to get the command-line arguments to work, such that I don't need to convert anything myself, i..e maybe by changing the tmain function?
Thanks!
C
Update: example of invoking on command line:
Yep. so the way I invoke this on command line is:
progname.exe arg1 arg2,
where arg1 is a physics engine I am trying to load, and arg2 is a dae(physics file with physics info), so I go, specifically:
progname.exe Bullet E:/a.dae
Stepping into the line "PF->SelectEngine(argv[1]);" gives the following code:
bool palFactory::SelectEngine(const PAL_STRING& name) {
#ifdef INTERNAL_DEBUG
printf("palFactory::SelectEngine: this = %p\n", this);
#endif
SetActiveGroup(name); // also calls RebuildRegistry
return isClassRegistered("palPhysics");
}
, in this case, when debugging, I can see that const PAL_STRING& name, i.e. the string, is just "B", instead of what I would expect it to be, which is "Bullet", my command line argument I have passed in the command line.
I've been plauged by this problem for years. The only solution I've been able to find is to NOT USE Visual Studio. I've had to fall back to using other compilers when I must be able to process command-line args. Specifically, I've been using the Digital Mars compiler successfully. It handles the command-line args correctly. I use the VS environment for intellisense and debugging, then compile with DMC to deploy.
---edit below---
Turns out, I just wasn't asking the right question. I finally asked the right question, and got the right answer! See link below.
What is the difference between _tmain() and main() in C++?
I want to create a loadable DLL of some of my tcl methods. But I am not getting how to do this. For that I have taken a simple example of tcl api which adds two numbers and prints the sum. Now I want to create a loadable DLL for this to export this tcl functionality.
But I am not understanding how to do it in Visual Studio. I have written a C code which can call this tcl api and get the sum of two integers, but again I don't want it to do this way. I want to create a DLL file to use this tcl functionality. How can I create this DLL on Visual Studio 2010.
Below is my sample tcl program that I am using:
#!/usr/bin/env tclsh8.5
proc add_two_nos { } {
set a 10
set b 20
set c [expr { $a + $b } ]
puts " c is $c ......."
}
And here is the C code which can use this tcl functionality :
#include <tcl.h>
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char **argv) {
Tcl_Interp *interp;
int code;
char *result;
Tcl_FindExecutable(argv[0]);
interp = Tcl_CreateInterp();
code = Tcl_Eval(interp, "source myscript.tcl; add_two_nos");
/* Retrieve the result... */
result = Tcl_GetString(Tcl_GetObjResult(interp));
/* Check for error! If an error, message is result. */
if (code == TCL_ERROR) {
fprintf(stderr, "ERROR in script: %s\n", result);
exit(1);
}
/* Print (normal) result if non-empty; we'll skip handling encodings for now */
if (strlen(result)) {
printf("%s\n", result);
}
/* Clean up */
Tcl_DeleteInterp(interp);
exit(0);
}
I have successfully compiled this code with the below command
gcc simple_addition_wrapper_new.c -I/usr/include/tcl8.5/ -ltcl8.5 -o simple_addition_op
The above code is working with the expected output.
What steps do I need to take to create a loadable dll for this in Visual Studio 2010?
If you look at the answers to this question: here it gives the basic outline of the process you need to go through. There are links from my answer to some Microsoft MSDN articles on creating DLLs.
To go into this in a little more detail for a C++ dll that has Tcl embedded in it.
The first step is to create a new visual studio project with the correct type, one that is going to build a dll that exports symbols. My example project is called TclEmbeddedInDll and that name appears in code in symbols such as TCLEMBEDDEDINDLL_API that are generated by Visual Studio.
The dllmain.cpp look like this:
// dllmain.cpp : Defines the entry point for the DLL application.
#include "stdafx.h"
BOOL APIENTRY DllMain( HMODULE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
{
allocInterp() ;
break ;
}
case DLL_THREAD_ATTACH:
break ;
case DLL_THREAD_DETACH:
break ;
case DLL_PROCESS_DETACH:
{
destroyInterp() ;
break;
}
}
return TRUE;
}
The allocInterp() and destroyInterp() functions are defined in the TclEmbeddedInDll.h, the reason for using functions here rather than creating the Tcl_Interp directly is that it keeps the details about Tcl away from the DLL interface. If you create the interp here then you have to include tcl.h and then things get complicated when you try and use the DLL in another program.
The TclEmbeddedInDll.h and .cpp are shown next, the function fnTclEmbeddedInDll() is the one that is exported from the DLL - I'm using C linkage for this rather than C++ as it makes it easier to call the function from other languages IMHO.
// The following ifdef block is the standard way of creating macros which make exporting
// from a DLL simpler. All files within this DLL are compiled with the TCLEMBEDDEDINDLL_EXPORTS
// symbol defined on the command line. This symbol should not be defined on any project
// that uses this DLL. This way any other project whose source files include this file see
// TCLEMBEDDEDINDLL_API functions as being imported from a DLL, whereas this DLL sees symbols
// defined with this macro as being exported.
#ifdef TCLEMBEDDEDINDLL_EXPORTS
#define TCLEMBEDDEDINDLL_API __declspec(dllexport)
#else
#define TCLEMBEDDEDINDLL_API __declspec(dllimport)
#endif
extern "C" {
TCLEMBEDDEDINDLL_API void fnTclEmbeddedInDll(void);
}
void allocInterp() ;
void destroyInterp() ;
// TclEmbeddedInDll.cpp : Defines the exported functions for the DLL application.
//
#include "stdafx.h"
extern "C" {
static Tcl_Interp *interp ;
// This is an example of an exported function.
TCLEMBEDDEDINDLL_API void fnTclEmbeddedInDll(void)
{
int code;
const char *result;
code = Tcl_Eval(interp, "source simple_addition.tcl; add_two_nos");
result = Tcl_GetString(Tcl_GetObjResult(interp));
}
}
void allocInterp()
{
Tcl_FindExecutable(NULL);
interp = Tcl_CreateInterp();
}
void destroyInterp()
{
Tcl_DeleteInterp(interp);
}
The implementation of allocInterp() and destroyInterp() is very naive, no error checking is done.
Finally for the Dll the stdafx.h file ties it all together like this:
// stdafx.h : include file for standard system include files,
// or project specific include files that are used frequently, but
// are changed infrequently
//
#pragma once
#include "targetver.h"
#define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers
// Windows Header Files:
#include <windows.h>
// TODO: reference additional headers your program requires here
#include <tcl.h>
#include "TclEmbeddedInDll.h"
I'm having a really hard time getting an R library installed that requires some compilation in C. I'm using a Mac OSX Snow Leopard machine and trying to install this R package (here).
I've looked at the thread talking about getline on macs and have tried a few of these fixes, but nothing is working! I'm a newbie and don't know any C, so that may be why! Can anyone give me some tips on how I could modify files in this package to get it to install?? Anyhelp would be pathetically appreciated! Here's the error I'm getting:
** libs
** arch - i386
g++ -arch i386 -I/Library/Frameworks/R.framework/Resources/include -I/Library/Frameworks/R.framework/Resources/include/i386 -I/usr/local/include -D_FASTMAP -DMAQ_LONGREADS -fPIC -g -O2 -c bed2vector.C -o bed2vector.o
In file included from /usr/include/c++/4.2.1/backward/strstream:51,
from bed2vector.C:8:
/usr/include/c++/4.2.1/backward/backward_warning.h:32:2: warning: #warning This file includes at least one deprecated or antiquated header. Please consider using one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples include substituting the <X> header for the <X.h> header for C++ includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated.
bed2vector.C: In function ‘int get_a_line(FILE*, BZFILE*, int, std::string&)’:
bed2vector.C:74: error: no matching function for call to ‘getline(char**, size_t*, FILE*&)’
make: *** [bed2vector.o] Error 1
chmod: /Library/Frameworks/R.framework/Resources/library/spp/libs/i386/*: No such file or directory
ERROR: compilation failed for package 'spp'
The easiest solution is probably to add a static definition for getline() to bed2vector.c. This might be good enough:
/* PASTE AT TOP OF FILE */
#include <stdio.h> /* flockfile, getc_unlocked, funlockfile */
#include <stdlib.h> /* malloc, realloc */
#include <errno.h> /* errno */
#include <unistd.h> /* ssize_t */
extern "C" ssize_t getline(char **lineptr, size_t *n, FILE *stream);
/* PASTE REMAINDER AT BOTTOM OF FILE */
ssize_t
getline(char **linep, size_t *np, FILE *stream)
{
char *p = NULL;
size_t i = 0;
if (!linep || !np) {
errno = EINVAL;
return -1;
}
if (!(*linep) || !(*np)) {
*np = 120;
*linep = (char *)malloc(*np);
if (!(*linep)) {
return -1;
}
}
flockfile(stream);
p = *linep;
for (int ch = 0; (ch = getc_unlocked(stream)) != EOF;) {
if (i > *np) {
/* Grow *linep. */
size_t m = *np * 2;
char *s = (char *)realloc(*linep, m);
if (!s) {
int error = errno;
funlockfile(stream);
errno = error;
return -1;
}
*linep = s;
*np = m;
}
p[i] = ch;
if ('\n' == ch) break;
i += 1;
}
funlockfile(stream);
/* Null-terminate the string. */
if (i > *np) {
/* Grow *linep. */
size_t m = *np * 2;
char *s = (char *)realloc(*linep, m);
if (!s) {
return -1;
}
*linep = s;
*np = m;
}
p[i + 1] = '\0';
return ((i > 0)? i : -1);
}
This doesn't handle the case where the line is longer than the maximum value that ssize_t can represent. If you run into that case, you've likely got other problems.
Zeroth question: Have you considered using a package manager like fink or MacPorts rather than compiling yourself? I know that fink has an R package.
First question: How is the R build managed? Is there a ./configure? If so have you looked at the options to it? Does it use make? Scons? Some other dependency manager?
Second question: Have you told the build system that you are working on a Mac? Can you specify that you don't have a libc with native getline?
If the build system doesn't support Mac OS---but I image that R's does---you are probably going to have to download the standalone version, and hack the build to include it. How exactly you do that depends on the build system. And you may need to hack the source some.