CODEWITHSUNDEEP
c++openglg++glfw
Michael Rothkopf
Michael Rothkopf

Reputation: 128

GLFW_PRESS throws "lvalue required as left operand of assignment"

I am trying to make a simple GLFW key callback function using the provided code in the documentation:

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) {
    if (key == GLFW_KEY_W && action = GLFW_PRESS) {
        glTranslatef(0.25f, 0, 0);
    }
    if (key == GLFW_KEY_A && action = GLFW_PRESS) {
        glTranslatef(0, 0, 0.25f);
    }
    if (key == GLFW_KEY_S && action = GLFW_PRESS) {
        glTranslatef(-0.25f, 0, 0);
    }
    if (key == GLFW_KEY_D && action = GLFW_PRESS) {
        glTranslatef(0, 0, -0.25f);
    }
}

However, G++ throws the error:

glfw3.h:310:37: error: lvalue required as left operand of assignment
  310 | #define GLFW_PRESS                  1
      |                                     ^
main.cpp:70:36: note: in expansion of macro 'GLFW_PRESS'
   70 |  if (key == GLFW_KEY_W && action = GLFW_PRESS) {

for every one of these "if" statements.

I encountered it when compiling with this command: g++ main.cpp -lopengl32 -lglu32 -lglfw3 -mwindows. I have correctly installed GLFW with MinGW, that compiles fine on its own.

Upvotes: 1

Views: 66

Answers (1)

Michael Rothkopf
Michael Rothkopf

Reputation: 128

The problem was a syntax error, using = instead of ==.

Upvotes: 1

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