Function lookforfunc

3rd/lua-5.4.3/src/loadlib.c:390–408

** Look for a C function named 'sym' in a dynamically loaded library ** 'path'. ** First, check whether the library is already loaded; if not, try ** to load it. ** Then, if 'sym' is '*', return true (as library has been loaded). ** Otherwise, look for symbol 'sym' in the library and push a ** C function with that symbol. ** Return 0 and 'true' or a function in the stack; in case of ** errors, ret

** errors, return an error code and an error message in the stack.
*/
static int lookforfunc (lua_State *L, const char *path, const char *sym) {
  void *reg = checkclib(L, path);  /* check loaded C libraries */
  if (reg == NULL) {  /* must load library? */
    reg = lsys_load(L, path, *sym == '*');  /* global symbols if 'sym'=='*' */
    if (reg == NULL) return ERRLIB;  /* unable to load library */
    addtoclib(L, path, reg);
  }
  if (*sym == '*') {  /* loading only library (no function)? */
    lua_pushboolean(L, 1);  /* return 'true' */
    return 0;  /* no errors */
  }
  else {
    lua_CFunction f = lsys_sym(L, reg, sym);
    if (f == NULL)
      return ERRFUNC;  /* unable to find function */
    lua_pushcfunction(L, f);  /* else create new function */
    return 0;  /* no errors */
  }
}


static int ll_loadlib (lua_State *L) {