SDL2/SDL.h causing undefined references in Non-SDL code - reference

Question

I've been having an awfully strange problem that I cannot seem to grasp. I'm almost convinced that this is a compiler bug.
xTech : xIncludes.hh
#ifndef _xIncludes_
#define _xIncludes_
#define SDL_MAIN_HANDLED
#include <string.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdint.h>
#include <vector>
#include <SDL2/SDL.h>
#if defined _WIN32
#include <winsock.h>
#endif
#endif
xTech : xSound.cc
#include "xSound.hh"
int xOGGStreamSource::_stream(ALuint Buffer) {
char data[BufferSize];
int size = 0;
int section;
int result;
while (size < BufferSize) {
result = ov_read(&_oggstream, data + size, BufferSize - size, 0, 2, 1, &section);
if (result > 0)
size += result;
else
if (result < 0)
return result;
else
break; //This seems a little redundant.... deal with it after it works.
}
if (size == 0) return 0;
alBufferData(Buffer, _format, data, size, _vorbisinfo->rate);
return 1;
}
void xOGGStreamSource::_empty() {
int queued;
alGetSourcei(_source, AL_BUFFERS_QUEUED, &queued);
while (queued--) {
ALuint Buffer;
alSourceUnqueueBuffers(_source, 1, &Buffer);
}
}
int xOGGStreamSource::Open(xString path) {
int result;
_oggfile = xOpenFile(path, "rb");
if (_oggfile.Buffer == NULL) {
xLogf("Audio", "Error in OGG File '%s', file does not exist.", path);
return -3;
}
if (result = ov_open(_oggfile.Buffer, &_oggstream, NULL, 0) < 0) {
xLogf("Audio", "Error in OGG File '%s', file is non-OGG.", path);
xCloseFile(_oggfile);
return -2;
}
_vorbisinfo = ov_info(&_oggstream, -1);
_vorbiscomment = ov_comment(&_oggstream, -1);
if (_vorbisinfo->channels == 1)
_format = AL_FORMAT_MONO16;
else
_format = AL_FORMAT_STEREO16;
alGenBuffers(2, _buffers);
alGenSources(1, &_source);
return 1;
}
void xOGGStreamSource::Close() {
alSourceStop(_source);
_empty();
alDeleteSources(1, &_source);
alDeleteBuffers(1, _buffers);
ov_clear(&_oggstream);
}
int xOGGStreamSource::Playback() {
if (Playing()) return 1;
if (!_stream(_buffers[0])) return 0;
if (!_stream(_buffers[1])) return 0;
alSourceQueueBuffers(_source, 2, _buffers);
alSourcePlay(_source);
return 1;
}
int xOGGStreamSource::Playing() {
ALenum state;
alGetSourcei(_source, AL_SOURCE_STATE, &state);
return (state == AL_PLAYING);
}
int xOGGStreamSource::Update(xVec3f_t Pos, xVec3f_t Vloc, xVec3f_t Dir, float Vol) {
int processed;
int active = 1;
alSource3f(_source, AL_POSITION, Pos.X, Pos.Y, Pos.Z);
alSource3f(_source, AL_VELOCITY, Vloc.X, Vloc.Y, Vloc.Z);
alSource3f(_source, AL_DIRECTION, Dir.X, Dir.Y, Dir.Z);
alSourcef (_source, AL_GAIN, Vol);
alSourcei (_source, AL_SOURCE_RELATIVE, AL_TRUE);
alGetSourcei(_source, AL_BUFFERS_PROCESSED, &processed);
while(processed--) {
ALuint Buffer;
alSourceUnqueueBuffers(_source, 1, &Buffer);
active = _stream(Buffer);
alSourceQueueBuffers(_source, 1, &Buffer);
}
return active;
}
xSound::xSound(xOGGStreamSource xss) { _source = xss; }
int xSound::PlaySound(float Volume, xVec3f_t Location) {
if (!_source.Playback()) return -3;
while(_source.Update(Location, xVec3f_t(0,0,0), xVec3f_t(0,0,0), Volume)) {
if (!_source.Playing()) {
if (!_source.Playback()) return -2;
else return -1;
}
}
_source.Close();
return 1;
}
xSoundManager::xSoundManager(){}
int xSoundManager::Init() {
_device = alcOpenDevice(NULL);
if (!_device) return -2;
_context = alcCreateContext(_device, NULL);
if (alcMakeContextCurrent(_context) == ALC_FALSE || !_context) return -1;
if (!Volume) {
xLogf("Error", "Volume in Audio is not set properly. Setting to default");
Volume = DEFAULT_VOLUME;
}
alListenerf(AL_GAIN, Volume);
if (!BufferSize) {
xLogf("Error", "Buffer size in Audio is not set properly. Setting to default");
BufferSize = DEFAULT_BUFFER_SIZE;
}
return 0;
}
xSound* xSoundManager::LoadOGG(xString file) {
xOGGStreamSource ogg;
if (ogg.Open(file) < 0) return NULL;
return new xSound(ogg);
}
xTechLibTest : main.cc
int main() {
xSetLogFile("xTechLibTest.log");
xSoundManager* audio = new xSoundManager();
if (audio->Init() < 0) return -1;
xSound* testsound1 = audio->LoadOGG("testsound.ogg");
if (testsound1 == NULL) return -2;
testsound1->PlaySound(1.0, xVec3f_t(1.0,0.5,0.3));
}
The above code and everything associated with it (string implementations, etc) work fine, no problems at all. That is until I include SDL.h; I get undefined references for every function I defined, when the compiler could find them with no problem before. It seems that the mere inclusion of SDL.h completely nullifies any definition I make. Any ideas what's going on here?

Answer 1

Have you properly included the linkage to the SDL libraries?
If you have built the binaries yourself, you need to include the path and library. On a linux system, if you have built the static libraries yourself, you will have a binary called libSDL2.a, however to link you need to specify SDL2 as your linked library.
Also as a side note, do you have a redundant include guard on your xsound.h file( via #ifdef _xsound_ ... ) ?
p.s. It will help the other users if you specify what how your environment is setup; compiler, system os, IDE.

Answer 2

It would be useful to see the output from your compiler/linker.
I've had similar problems with network related code when using Cygwin on a windows machine. I've had sockets working fine without SDL, as soon as I include SDL, the whole lot breaks with messages saying that certain header files and references can't be found.
I'm not certain, but I think it has something to do with the way that SDL has it's own main macros (here is a post about it here - simple tcp echo program not working when SDL included?).
I may be wrong, but is this similar to what you are seeing?