I'm trying to compile my first GStreamer plugin with Visual Studio 2013 (v120). But when I'm trying to init GValue type list
g_value_init (&va, GST_TYPE_LIST);
I get
error LNK2001: unresolved external symbol _gst_value_list_type
I found out that _gst_value_list_type is defined like this
extern GType _gst_value_list_type;
/**
* GST_TYPE_LIST:
*
* a #GValue type that represents an unordered list of #GValue values. This
* is used for example to express a list of possible values for a field in
* a caps structure, like a list of possible sample rates, of which only one
* will be chosen in the end. This means that all values in the list are
* meaningful on their own.
*
* Returns: the #GType of GstValueList (which is not explicitly typed)
*/
#define GST_TYPE_LIST (_gst_value_list_type)
but I have no idea where to find it
I have correct header files included and I have tried to link every lib there is from gstreamers but without any success. I'm using last version of gstreamer downloaded from here
Try to include
#include <gst/gstconfig.h>
#include <gst/gstcaps.h>
#include <gst/gststructure.h>
#include <gst/gstcapsfeatures.h>
#include <gst/gst.h>
One by one. Please answer if its helps.
I think when you compile, your include path see different area.
in my case, i have two gstreamer include path
(/usr/include/gstreamer-1.0 and /usr/local/include/gstreamer-1.0)
in the /usr/include/gstreamer-1.0
GST_TYPE_LIST is defined below
#define GST_TYPE_LIST gst_value_list_get_type()
in the /usr/local/include/gstreamer-1.0
GST_TYPE_LIST is defined below
#define GST_TYPE_LIST (_gst_value_list_type)
After changing include path to /usr/include/gstreamer-1.0, I solve the problem.
Related
I'm working on a project which requires to develop the firmware for several esp32. All the microcontrollers share a common code that takes care of wifi and mqtt, however they all have a different behavior, which is defined in a specific component. The structure of my project is something like this:
- CMakeLists.txt
- Makefile
- sdkconfig
- main
- CMakeLists.txt
- main.c
- components
- wifi_fsm
- wifi_fsm.h
- wifi_fsm.c
- CMakeLists.txt
- mqtt_fsm
- mqtt_fsm.h
- mqtt_fsm.c
- CMakeLists.txt
- entity_1
- entity_1.h
- entity_1.c
- CMakeLists.txt
- entity2
- entity2.h
- entity2.c
- CMakeLists.txt
...
Each entity defines some functions with standard names, which implement specific logic for the entity itself and which are called within the shared code (main, wifi_fsm, mqtt_fsm).
void init_entity(); // called in main.c
void http_get(char *buf); // called in wifi_fsm
void http_put(char *buf);
void mqtt_msg_read(char *buf); // called in mqtt_fsm
void mqtt_msg_write(char *buf);
My idea was to have a conditional statement to include at will a specific behavior, so that depending on the entity included, the compiler would link the calls to the functions above to those found in the specific included library. Therefore, at the beginning of main.c I just added the following lines with the goal of having to change the only defined pre-processor symbol to compile for different enity behaviors.
#define ENTITY_1
#ifdef ENTITY_1
#include "entity_1.h"
#elif defined ENTITY_2
#include "entity_2.h"
#elif ...
#endif
#include "wifi_fsm.h"
#include "mqtt_fsm.h"
void app_main(void)
{
while(1){
...
}
}
On the one hand the compiler apparently works fine, giving successful compilation without errors or warnings, meaning that the include chain works correctlty otherwise a duplicate name error for the standard functions would be thrown. On the other hand, it always links against the first entity in alphabetical order, executing for instance the code included in the init_entity() of the component entity_1. If I rename the standard functions in entity_1, then it links against entity_2.
I can potentially use pointers to standard calls to be linked to specific functions in each entity if the approach above is wrong, but I would like to understand first what is wrong in my approach.
EDIT in response to Bodo's request (content of the CMakeFile.txt)
Project:
cmake_minimum_required(VERSION 3.5)
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
project(proj)
Main:
set(COMPONENT_REQUIRES )
set(COMPONENT_PRIV_REQUIRES )
set(COMPONENT_SRCS "main.c")
set(COMPONENT_ADD_INCLUDEDIRS "")
register_component()
Component:
set(COMPONENT_SRCDIRS "src")
set(COMPONENT_ADD_INCLUDEDIRS "include")
set(COMPONENT_REQUIRES log freertos driver nvs_flash esp_http_server mqtt)
register_component()
This answer is based on guessing because I don't have enough information. For the same reason it is incomplete in some parts or may not fully match the use case of the question.
The details about how the project will be built seems to be hidden in a cmake include file like project.cmake or nested include files.
My guess is that the build system creates libraries from the source code of every individual component and then links the main object file with the libraries. In this case, the linker will find a symbol like init_entity in the first library that fulfills the dependency. This means the library (=component) listed first in the linker command line will be used.
If the linker command line would explicitly list the object files entity_1.o and entity_2.o, I would expect an error message about a duplicate symbol init_entity.
I can propose two ways to solve the problem:
Make sure only the selected entity is used to build the program.
Make the identifier names unique in all entities and use preprocessor macros to choose the right one depending on the selected entity.
For the first approach you can use conditionals in CMakeLists.txt. See https://stackoverflow.com/a/15212881/10622916 for an example. Maybe the register_component() is responsible for adding the component to the build. In this case you could wrap this in a condition.
BUT modifying the CMakeLists.txt might be wrong if the files are generated automatically.
For the second approach you should rename the identifiers in the entities to make them unique. The corresponding header files can define a macro to replace the common name intended for the identifier with the specific identifier of the selected entity.
In the code that uses the selected entity you will always use the common name, not the individual names.
Example:
entity_1.c:
#include "entity_1.h"
void init_entity_1(void)
{
}
entity_2.c:
#include "entity_2.h"
void init_entity_2(void)
{
}
entity_1.h:
void init_entity_1(void);
// This replaces the token/identifier "init_entity" with "init_entity_1" in subsequent source lines
#define init_entity init_entity_1
// or depending on the parameter list something like
// #define init_entity() init_entity_1()
// #define init_entity(x,y,z) init_entity_1(y,x,z)
entity_2.h:
void init_entity_2(void);
#define init_entity init_entity_2
main.c
#define ENTITY_1
#ifdef ENTITY_1
#include "entity_1.h"
#elif defined ENTITY_2
#include "entity_2.h"
#elif ...
#endif
void some_function(void)
{
init_entity();
}
In this example case with #define ENTITY_1, the preprocessor will change some_function to
void some_function(void)
{
init_entity_1();
}
before the compilation step and the linker will use init_entity_1 from entity_1.c. An optimizing linker may then omit the object file entity_2.o or the corresponding library because it is unused.
I am developing a C application, and using Eclipse CDT IDE, which I find great. The project uses Glib,Gtk,and GStreamer , so whenever I use some of their features in a file, I need to include:
#include <glib.h>
#include <gtk/gtk.h>
#include <gst/gst.h>
The code compiles without any error, since the PATH variable to search those headers is set correctly in a CMakeLists.txt.
However, while working on the project, I found annoying errors highlighting in my code, regarding type definitions like gchar or GValue or GTKApplication; the error outlined is "symbol **** could not be resolved". These definitions are inside a header file that my Eclipse IDE cannot find (included by glib.h), if not at compile time (indeed the program compiles correctly). Instead, the type GError , defined in gst.h , is not highlighted as an error by the pre-compiler.
I would like then that my Eclipse IDE could search on nested headers (#include inside an #inlcude inside...) to find those type definition, in order so to not have those annoying errors highlighting. How can I do so? I would not like to have to include directly all files where the type definitions are done.
EDIT: As Jonah Graham outlined, the problem is not beacuse Eclispe does a "single-step research" on the headers, since it inspects includes inside other includes like any other IDE. It is a CMake bug with c and Eclipse
Thanks in advance.
The problem you are facing is a CMake bug*. CMake adds __cplusplus into the defined symbols unconditionally, which means that glib headers are not parsed properly when in C mode. You can see this clearly by opening gmacros.h around the definition for G_BEGIN_DECLS:
Because CMake told CDT __cplusplus is defined, it thinks G_BEGIN_DECLS is also defined, which makes code like this from gtypes.h parse incorrectly:
G_BEGIN_DECLS
/* Provide type definitions for commonly used types.
* These are useful because a "gint8" can be adjusted
* to be 1 byte (8 bits) on all platforms. Similarly and
* more importantly, "gint32" can be adjusted to be
* 4 bytes (32 bits) on all platforms.
*/
typedef char gchar;
...
Of course with no gchar defined, everything else is going to go badly.
Luckily there is a quick workaround until the problem is resolved in CMake, remove __cplusplus from the info in CDT.
Open Project Properties
C/C++ Include Paths and Symbols
Remove __cplusplus from the list and press OK
(sometimes necessary) Right-click on project -> Index -> Rebuild
* There may be some other workarounds if you know CMake better. The bug says also it will be fixed for the next release of CMake.
This issue is due to doxygen parsing constraints. I am using doxygen 1.8.11 with Eclox (the eclipse plugin) in Kinetis Design Studio for embedded C development.
Almost all of the doxygen compiling works, except I need to have a few very large static arrays. I didn't want to clutter up the main code, so I used a hack I found on these forums (https://stackoverflow.com/a/4645515/6776259):
static const float Large_Array[2000] = {
#include "Comma_Delimited_Text_File.txt"
};
Unfortunately, that hack is causing the compile of my main.c main_module group to fail. With the following error:
warning: end of file while inside a group
I've tried excluding those constants from my main_module group with something like the following:
/*!
** #addtogroup main_module
** #{
*/
...
... header code ...
...
/*!
** #}
*/
static const float Large_Array[2000] = {
#include "Comma_Delimited_Text_File.txt"
};
/*!
** #addtogroup main_module
** #{
*/
...
More code, definitions, etc.
None of this is generated in the doxygen compile...?
/*!
** #}
*/
This gets rid of the doxygen compiling error, but the compiled doxygen documentation does not include anything after the Large_Array declaration. So it seems the second #addtogroup statement is not working.
Am I missing something simple? Any help is appreciated. Thank you.
If Comma_Delimited_Text_File.txt doesn't have trailing linebreak, then try adding one.
Doxygen gets confused if include file doesn't end with linebreak. This can break the document generation for other files too, even when they don't seem related. Often this results in missing symbols and broken callgraphs.
I'm having an issue with compiling code for Arduino if the code is in multiple files. What I have been doing in the past is have a script concatenate the files in another directory and make the project there. I would like to be able to compile directly from my build folder without having to jump through hoops of making sure everything is defined in the right order, etc.
I'm using avrdude to compile from Linux command line, because the Arduino IDE doesn't work very well with my window manager. When I make with multiple files (with appropriate #include statements, I get errors of the following nature, but for all of my methods and variables.
./../lib/motor.ino:3:21: error: redefinition of ‘const long unsigned int MOVE_DELAY’
./../lib/motor.ino:3:21: error: ‘const long unsigned int MOVE_DELAY’ previously defined here
The only other place that MOVE_DELAY is used is inside the void loop() function, and it doesn't redefine it there. The code also compiles fine if concatenate it into one file and run make in that directory, but not if they are in separate files with includes.
I believe your problem is solvable by declaring the objects with the "extern" prefix or external. For example. I often use the SdFat library, in which it is included in both my main sketch and instanced in other libraries.
/**
* \file test.ino
*/
#include <SdFat.h>
#include <foo.h>
SdFat sd;
...
Where I also use the same object in other libraries, such as foo.h.
/**
* \file foo.h
*/
#include <SdFat.h>
extern SdFat sd;
...
If it was not for the prefix of "extern" it would error like yours, as "sd" can not exist twice. Where the extern prefix tells the linker don't make a new instantiation, rather link to the externally instance elsewhere.
I have been having these really odd problems with Visual Studio 2010. At this point, the behavior is so erratic that I really wish I did not have to use it for CUDA (I know I don't have to, but it is hard not to use it).
One of the many problems I have been having with really basic stuff is header files being included more than once. For example:
//vars.cuh
#if !defined(VARS_cuh)
#define VARS_cuh
#include <cuda.h>
#include <cuda_runtime_api.h>
int* kern_xstart, *kern_xend, *kern_ystart, *kern_yend, *kern_zstart, *kern_zend;
/* more variable definitions */
#endif
I then include this file in most of my source files:
//source_file.cu
extern "C"{
#include "vars.cuh"
/* more includes of my own headers */
#include <cuda.h>
#include <cuda_runtime_api.h>
}
/* source file body */
The VS 2010 compiler puts out errors like this: "error LNK2005: foo already defined in other_source_file_I_wrote.cu.obj"
Why is it doing this? Also, to kill two birds with one stone, with this setup, I also have problems with writing a function in source_file.cu, and then prototyping it in vars.cuh. The problem arrises that vars.cuh can't see the definition, even though I am clearly including vars.cuh in source_file.cu!
Thank you!
The header file is being compiled multiple times because, as you say, you include this header file in most of your source files. Those global variables are included in multiple source files and thus are defined in every source file that includes the header. When the linker links all of the object files together, it finds multiple definitions of those variables, hence the error.
If you want to share global variables across multiple source files, declare them as extern in the header, then define each of them once in one source file.
This isn't a problem with Visual Studio or the Visual C++ compiler, it's how C works.