OpenGL and SDL '#version required and missing' but working in debug - c++

Question

I'm fairly noobish with C++ so it's probably a bit too early to get into this sorta thing, but anyway. I've been working on setting up a simple triangle in OpenGL and SDL but I have some weird things happening already. The first thing is that when I compile it I get one of three errors:
Line 194: ERROR: Compiled vertex shader was corrupt.
Line 156: ERROR: 0:1: '' : #version required and missing. ERROR: 0:1: '<' : syntax error syntax error
Line 126: ERROR: 0:1: '' : #version required and missing.
ERROR: 0:1: 'lour' : syntax error syntax error
Like literally I just repeatedly hit the build button and it seems completely random whether it displays one or the other of the messages. Ok, so that's weird but what's weirder is that when I run it in debug mode (i.e I put a breakpoint and step through everything) it works perfectly, for no apparent reason.
So, I've come to the conclusion that I've done something stupid with memory, but in any case here is the relevant code (ask if you want to see more):
Read File Function
std::string readFile(std::string name) {
std::ifstream t1(name.c_str());
if (t1.fail()) {
std::cout << "Error loading stream" << "\n";
}
std::stringstream buffer;
buffer << t1.rdbuf();
std::string src = buffer.str();
std::cout << src << std::endl;
return src;
}
Compile Shaders
const char *vSource = readFile("vertexShader.gl").c_str();
// Read fragment shader
const char *fSource = readFile("fragmentShader.gl").c_str();
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vs, 1, &vSource, NULL);
glCompileShader(vs);
GLint isCompiled = 0;
glGetShaderiv(vs, GL_COMPILE_STATUS, &isCompiled);
if(isCompiled == GL_FALSE) { // ... Error stuff here...
N.B there's a fragment shader compiling bit which looks exactly the same. Lines 126 and 156 are in the error stuff part of the vertex and fragment shaders respectively.
Link Shaders
shader_programme = glCreateProgram();
glAttachShader(shader_programme, vs);
glAttachShader(shader_programme, fs);
glLinkProgram(shader_programme);
GLint isLinked = 0;
glGetProgramiv(shader_programme, GL_LINK_STATUS, (int *)&isLinked);
if(isLinked == GL_FALSE) { // ... Error stuff ... }
glDetachShader(shader_programme, vs);
glDetachShader(shader_programme, fs);
You can see the shaders if you want but they work (as in the fragment shader shows the correct colour in debug mode) so I don' think that they are the problem.
I'm on OSX using SDL2, OpenGL v3.2, GLSL v1.50 and Xcode 4 (and yes I did the text file thing if you know what I mean).
Sorry for posting a lot of code - if anyone has any tips on how to debug memory leaks in Xcode that might help, but thanks anyway :)

Answer 1

you throw away the strings as soon as you read them leading to the vSource referencing deleted memory (and undefined behavior), instead keep the sources as std::string while you need the char* to remain valid:
std::string vSource = readFile("vertexShader.gl");
char* vSourcecharp = vSource.c_str();
// Read fragment shader
std::string fSource = readFile("fragmentShader.gl");
char* fSourcecharp = fSource.c_str();
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vs, 1, &vSourcecharp, NULL);
glCompileShader(vs);