dlsym(3)                                                       dlsym(3)

  dlsym()

  NAME

    dlsym() - get the address of a symbol from a dynamically-linked object

  SYNOPSIS

    #include 

    void *dlsym(void *handle, const char *name)

  DESCRIPTION

    The dlsym(3) call retrieves the address of a symbol defined in the object
    referenced by handle. The object must have already been opened by a call
    to dlopen(3). The symbol is stored in name as a character string.

    If loading the object referenced by handle caused other objects to be
    automatically loaded, all of those objects are searched by the dlsym(3)
    call. Dlsym(3) operations on the global symbol object use load ordering.
    However, the symbols are resolved in dependency order (see the dlopen(3)
    reference page).

  RETURN VALUES

    The dlsym(3) call returns NULL if the handle doesn't refer to a valid
    object, or if the symbol can't be found in any of the objects associated
    with handle. For more detailed information, use dlerror(3).

  EXAMPLE

    Here's a brief example of using dlopen(3) and dlsym(3):

    void *handle;
    int  *iptr, (*fptr)(int);
    /* open the object */
    handle = dlopen("/usr/lib/libc.so", RTLD_LAZY);
    /* find the address of a data object */
    iptr = (int *)dlsym(handle, "an_object");
    /* find the address of a function */
    fptr = (int (*)(int))dlsym(handle, "a_function");

  NOTES

    There is a special purpose value for handle, RTLD_NEXT, that is reserved
    for future use.

  SEE ALSO

    dlclose(3)

    dlerror(3)

    dlopen(3)

  USAGE NOTES

    The dlsym function is thread safe.

    The dlsym function is not async-signal safe.