Can't get bitmap of glyph from TrueType font file with stb_truetype library

Question

I'm trying to use stb_truetype "header-only" library for rendering glyphs from TrueType fonts (.ttf) into bitmaps, so I can use them further, but something goes wrong, and bitmap empty

Here include of library:

#define STB_TRUETYPE_IMPLEMENTATION
#include <stb_truetype.h>

And code, that should load font, render glyph of "1" (I guess?) into bitmap and use it to create OpenGL texture:

std::ifstream file(path, std::ios::binary);
if (file.is_open())
{
    std::vector<unsigned char> file_data;


    char file_data_char;

    while (file.get(file_data_char))
    {
        file_data.push_back(file_data_char);
    }

    file.close();



    stbtt_fontinfo font;
    stbtt_InitFont(&font, file_data.data(), 0);
    unsigned char* bitmap = stbtt_GetCodepointBitmap(&font, 100, 100, 49, 0, 0, 0, 0);



    unsigned int texture;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, 100, 100, 0, GL_RED, GL_UNSIGNED_BYTE, bitmap);
}

As result, font file loads fine, and seems initialization of font is fine as well, but bitmap empty, and texture is just nothing

I checked examples and discriptions in header (but maybe miss something important, not sure), tried to rewrite by some different ways and for some different glyph, and this still doesn't work