Why is printf not working?

Why is printf not working?

Printf is not the thing being buffered, it’s stdio, so all similar functions will behave in the same way. To demonstrate the buffering, all you have to do is printf a lot of characters, usually more than 1024, and printf will print as you will have exceeded the maximum buffer length and it will automatically fflush.

How do you call a function in a shared library?

Put your main function’s prototype in a . h file and include it in both your main and dynamic library code. With GCC, simply compile your main program with the -rdynamic flag. Once loaded, your library will be able to call the function from the main program.

Which of the following options is necessary to create a shared library?

Creating a Shared Library The -shared or -dynamiclib option is required to create a shared library.

Does printf use buffer?

To clarify the title of the question: printf(..) does not do any flushing itself, it’s the buffering of stdout that may flush when seeing a newline (if it’s line-buffered).

Which of the following printf statements will not print a string?

printf() is not printing any thing because the string mentioned is empty and in if it will also return the number of character printed which is 0. So it will proceed in else block instead of if. Here a[] is empty and in if statement we are printing a[], hence nothing will be printed.

Where does GCC Look for shared libraries?

It looks in the default directories /lib then /usr/lib (disabled with the -z nodeflib linker option).

  • What is position independent code?
  • GCC first searches for libraries in /usr/local/lib, then in /usr/lib.
  • The default GNU loader, ld.so, looks for libraries in the following order: ↩

What is Rpath in GCC?

In computing, rpath designates the run-time search path hard-coded in an executable file or library. Dynamic linking loaders use the rpath to find required libraries. Specifically, it encodes a path to shared libraries into the header of an executable (or another shared library).

Can shared library have main function?

Creating a shared library with main() [duplicate] In glibc (and also EGLIBC I believe), the libc.so library has a main() method: $ /lib/i386-linux-gnu/libc. so.

Is shared library executable?

Shared Libraries are loaded by the executable (or other shared library) at runtime. That makes them a little more complicated in that there’s a whole new field of possible hurdles which we will discuss in this post.

What is the difference between static and shared library?

Static libraries take longer to execute, because loading into the memory happens every time while executing. While Shared libraries are faster because shared library code is already in the memory.

What should be done for shared library based linking in GCC?

Step 1: Compiling with Position Independent Code. We need to compile our library source code into position-independent code (PIC): 1 $ gcc -c -Wall -Werror -fpic foo.c.

  • Step 2: Creating a shared library from an object file.
  • Step 3: Linking with a shared library.
  • Step 4: Making the library available at runtime.