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+title: Making C executables smaller
+keywords:C,linux,elf,optimizations
+
+# Making C executables smaller
+There are some simple things that can be done to make C executables as small as possible.
+Here is some example code we will work with:
+
+```c
+#include <SDL/SDL.h>
+ 
+char quit = 0;
+ 
+int main()
+{
+    SDL_Surface *screen,surface;
+    SDL_Event e;
+    SDL_Init( SDL_INIT_VIDEO );
+    screen = SDL_SetVideoMode( 400, 400, 32, SDL_SWSURFACE );
+    while(!quit)
+        while(SDL_PollEvent(&e)>0)
+        {
+            if(e.type==SDL_MOUSEBUTTONDOWN) quit=1;
+            if(e.type==SDL_KEYDOWN) quit=1;
+        }
+    SDL_Quit();
+}
+```
+
+Compile:
+```
+gcc main.c -o main -lSDL
+```
+
+Size before: 5326 bytes
+Execute command:
+```
+strip main
+```
+
+strip is included in most unix systems. It deletes some info
+symbols from executables
+
+Size after: 3532 bytes
+
+
+You can also try sstrip which is advanced version of strip.
+You can download it from 
+ELF kickers[2] webpage.
+
+
+Execute command:
+
+```
+sstrip main
+```
+
+Size after: 1960 bytes
+
+
+There are some others way to decrease size of program.
+GC Masher[3] Allows to
+brute force gcc options for smaller executable size.
+I where using this options for gcsmaher
+
+```
+-O  -O0  -O1  -O2  -O3  -Os
+-ffast-math
+-fomit-frame-pointer
+-fauto-inc-dec
+-mpush-args
+-mno-red-zone
+-mstackrealign 
+```
+
+After running with this options executable size is 5175 bytes and best compiling options are all possible combination. 
+Combining with sstrip gives 1960 bytes. And there size where not reduced but some time there can be saved some bytes.Now we will change main function with
+
+```c
+void _start()
+```
+
+and return change to
+```c
+asm ( \
+      "movl $1,%eax\n" \
+      "xor %ebx,%ebx\n" \
+      "int $128\n" \
+    );
+```
+
+One other thing is to archive your executable and cat it with unpack shell script.
+
+```bash
+a=/tmp/I;tail -n+2 $0|zcat>$a;chmod +x $a;$a;rm $a;exit
+```
+
+Best options and smallest size now is 563 byte. Nope this is not smallest size try to rename executable name to one symbol and you will get 4 extra bytes.
+
+```
+gcc -Os -ffast-math -fomit-frame-pointer 
+-fauto-inc-dec -mpush-args -mno-red-zone -c small.c;
+ld -dynamic-linker /lib/ld-linux.so.2 small.o /usr/lib/libSDL.so -o small;
+strip -s -R .comment -R .gnu.version small;sstrip small;
+7z a -tGZip -mx=9 small.gz small > /dev/null;
+cat unpack.header small.gz > small;
+chmod a+x small;rm small.gz small.o
+```
+
+
+
+
+Link to other resources source of example code[1].
+
+
+Author in link has 634 bytes. With his options I have 622 bytes and
+using gcmasher i have 606 bytes. I have used his source in this compare.
+
+
+## Links
+http://users.utu.fi/tmwire/linux4k.html  
+http://www.muppetlabs.com/%7Ebreadbox/software/elfkickers.html  
+http://pouet.net/prod.php?which=18479  
+
+## Downloads
+small_sdl_elf.zip -
+2KiB - http://archive.main.lv/files/writeup/list_elf_section_names/elf_section_list.zip
+