llo

llo-index.yml

@@ -12,7 +12,7 @@
     info:
       subdir: ""
       asciidoc: "adoc"
-      file: "nmap.adoc"
+      file: "hello.adoc"
       mimetype: "text/x-python"
     code:
       subdir: ""

swarmlab/llo/hello.adoc

@@ -0,0 +1,24 @@
+The classic example program for the C language is Hello World. Here is the source code for our version of the program:
+
+[source,c]
+----
+#include <stdio.h>
+
+int
+main (void)
+{
+  printf ("Hello, world!\n");
+  return 0;
+}
+----
+
+This compiles the source code in 'hello.c' to machine code and stores it in an executable file 'hello'. The output file for the machine code is specified using the -o option. This option is usually given as the last argument on the command line. If it is omitted, the output is written to a default file called 'a.out'.
+
+Note that if a file with the same name as the executable file already exists in the current directory it will be overwritten.
+
+The option -Wall turns on all the most commonly-used compiler warnings---it is recommended that you always use this option! There are many other warning options which will be discussed in later chapters, but -Wall is the most important. GCC will not produce any warnings unless they are enabled. Compiler warnings are an essential aid in detecting problems when programming in C and C++.
+
+In this case, the compiler does not produce any warnings with the -Wall option, since the program is completely valid. Source code which does not produce any warnings is said to compile cleanly.
+
+
+