How can I prevent segfault when hot reloading Zig code? | Zig Programming Language | Page 1

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This is my game.zig

📎 game.txt

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This is my main.zig

📎 message.txt

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The problem I'm referring to is in the readRadiusConfig function

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the segfault behavior seems a little unpredictable

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the ORIGINALLY COMPILED function is this:

fn readRadiusConfig(allocator: std.mem.Allocator) f32 {
    const default_value: f32 = 10.0;

    const config_data = std.fs.cwd().readFileAlloc(allocator, config_filepath, 1024 * 1024) catch {
        std.debug.print("Failed to read {s}\n", .{config_filepath});
        return default_value;
    };

    return std.fmt.parseFloat(f32, config_data[0 .. config_data.len - 1]) catch {
        std.debug.print("Failed to parse {s}\n", .{config_filepath});
        return default_value;
    };
}

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if I remove the file reading part and just return the default value like this:

fn readRadiusConfig(_: std.mem.Allocator) f32 {
    const default_value: f32 = 10.0;
    return default_value;
}

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it DOES NOT segfault, hot reload works fine.

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I can even add some more variables and still no segfault

fn readRadiusConfig(_: std.mem.Allocator) f32 {
    const default_value: f32 = 10.0;
    const new_value: f32 = 20;
    return default_value + new_value;
}

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But it will segfault if I do this:

fn readRadiusConfig(allocator: std.mem.Allocator) f32 {
    const default_value: f32 = 10.0;

    const new_value: f32 = 5.0;              // add this
    std.debug.print("{d}", .{new_value});    // add this

    const config_data = std.fs.cwd().readFileAlloc(allocator, config_filepath, 1024 * 1024) catch {
        std.debug.print("Failed to read {s}\n", .{config_filepath});
        return default_value;
    };

    return std.fmt.parseFloat(f32, config_data[0 .. config_data.len - 1]) catch {
        std.debug.print("Failed to parse {s}\n", .{config_filepath});
        return default_value;
    };
}

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can someone please explain to me why is this happening? is there a way that I fix this somehow?

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Thank you very much 🙏

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Or even this will segfault

fn readRadiusConfig(allocator: std.mem.Allocator) f32 {
    const default_value: f32 = 10.0;

    const config_data = std.fs.cwd().readFileAlloc(allocator, config_filepath, 1024 * 1024) catch {
        std.debug.print("Failed to read {s}\n", .{config_filepath});
        return default_value;
    };
    std.debug.print("{s}", .{config_data});

    return default_value;
}

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How can I prevent segfault when hot reloading Zig code?

#How can I prevent segfault when hot reloading Zig code?