feat: add hello

hello/config.txt

@@ -0,0 +1,33 @@
+# Example application configuration file
+
+version = "1.0";
+
+application:
+{
+  window:
+  {
+    title = "My Application";
+    size = { w = 640; h = 480; };
+    pos = { x = 350; y = 250; };
+  };
+
+  list = ( ( "abc", 123, true ), 1.234, ( /* an empty list */ ) );
+
+  books = ( { title  = "Treasure Island";
+              author = "Robert Louis Stevenson";
+              price  = 29.95;
+              qty    = 5; },
+            { title  = "Snow Crash";
+              author = "Neal Stephenson";
+              price  = 9.99;
+              qty    = 8; } );
+
+  misc:
+  {
+    pi = 3.141592654;
+    bigint = 9223372036854775807L;
+    columns = [ "Last Name", "First Name", "MI" ];
+    bitmask = 0x1FC3;	// hex
+    umask = 0027;	// octal. Range limited to that of "int"
+  };
+};

hello/example.cfg

@@ -0,0 +1,46 @@
+// An example configuration file that stores information about a store.
+
+// Basic store information:
+name = "Books, Movies & More";
+
+// Store inventory:
+inventory =
+{
+  books = ( { title  = "Treasure Island";
+              author = "Robert Louis Stevenson";
+              price  = 29.99;
+              qty    = 5; },
+            { title  = "Snow Crash";
+              author = "Neal Stephenson";
+              price  = 9.99;
+              qty    = 8; }
+          );
+
+  movies = ( { title = "Brazil";
+               media = "DVD";
+               price = 19.99;
+               qty = 11; },
+             { title = "The City of Lost Children";
+               media = "DVD";
+               price = 18.99;
+               qty = 5; },
+             { title = "Memento";
+               media = "Blu-Ray";
+               price = 24.99;
+               qty = 20;
+             },
+             { title = "Howard the Duck"; }
+           );
+};
+
+// Store hours:
+hours =
+{
+  mon = { open =  9; close = 18; };
+  tue = { open =  9; close = 18; };
+  wed = { open =  9; close = 18; };
+  thu = { open =  9; close = 18; };
+  fri = { open =  9; close = 20; };
+  sat = { open =  9; close = 20; };
+  sun = { open = 11; close = 16; };
+};

hello/main.c

@@ -0,0 +1,103 @@
+#include <stdio.h>
+//for use of exit()
+#include <stdlib.h>
+//for use of libconfig
+#include <libconfig.h>
+
+int main(int argc, char *argv[]) {
+  fprintf(stdout,"main() Started...\n");
+
+  /*read command line*/
+  if (argc > 1){
+    printf("main() argv[1]: %s\n", argv[1]);
+  }else{
+    fprintf(stderr, "Usage: %s <path to config file>\n", argv[0]);
+    exit(1);
+  }
+
+  config_t cfg;
+  config_setting_t *setting;
+  const char *str;
+
+  /*initialise new and EMPTY config*/
+  config_init(&cfg);
+
+  /* Read the file. If there is an error, report it and exit. */
+  if(! config_read_file(&cfg, argv[1]))
+  {
+    fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
+            config_error_line(&cfg), config_error_text(&cfg));
+    /*destroy config, BUT NOT the structure*/
+    config_destroy(&cfg);
+    return(EXIT_FAILURE);
+  }
+
+  /* Get the store name. */
+  if(config_lookup_string(&cfg, "name", &str))
+    printf("Store name: %s\n\n", str);
+  else
+    fprintf(stderr, "No 'name' setting in configuration file.\n");
+
+  /* Output a list of all books in the inventory. */
+  setting = config_lookup(&cfg, "inventory.books");
+  if(setting != NULL)
+  {
+    int count = config_setting_length(setting);
+    fprintf(stdout, "count: %d\n", count);
+    int i;
+
+    printf("%-30s  %-30s   %-6s  %s\n", "TITLE", "AUTHOR", "PRICE", "QTY");
+
+    for(i = 0; i < count; ++i)
+    {
+      config_setting_t *book = config_setting_get_elem(setting, i);
+
+      /* Only output the record if all of the expected fields are present. */
+      const char *title, *author;
+      double price;
+      int qty;
+
+      if(!(config_setting_lookup_string(book, "title", &title)
+           && config_setting_lookup_string(book, "author", &author)
+           && config_setting_lookup_float(book, "price", &price)
+           && config_setting_lookup_int(book, "qty", &qty)))
+        continue;
+
+      printf("%-30s  %-30s  $%6.2f  %3d\n", title, author, price, qty);
+    }
+    putchar('\n');
+  }
+
+  /* Output a list of all movies in the inventory. */
+  setting = config_lookup(&cfg, "inventory.movies");
+  if(setting != NULL)
+  {
+    unsigned int count = config_setting_length(setting);
+    fprintf(stdout, "count: %d\n", count);
+    unsigned int i;
+
+    printf("%-30s  %-10s   %-6s  %s\n", "TITLE", "MEDIA", "PRICE", "QTY");
+    for(i = 0; i < count; ++i)
+    {
+      config_setting_t *movie = config_setting_get_elem(setting, i);
+
+      /* Only output the record if all of the expected fields are present. */
+      const char *title, *media;
+      double price;
+      int qty;
+
+      if(!(config_setting_lookup_string(movie, "title", &title)
+           && config_setting_lookup_string(movie, "media", &media)
+           && config_setting_lookup_float(movie, "price", &price)
+           && config_setting_lookup_int(movie, "qty", &qty)))
+        continue;
+
+      printf("%-30s  %-10s  $%6.2f  %3d\n", title, media, price, qty);
+    }
+    putchar('\n');
+  }
+
+  config_destroy(&cfg);
+  fprintf(stdout,"main() Done.\n");
+  return(EXIT_SUCCESS);
+}

hello/makefile

@@ -0,0 +1,24 @@
+# Docu
+#
+#$@ is the name of the file to be made
+#$? is the names of the changed dependents
+#$< the name of the related file that caused the action
+#$* the prefix shared by target and dependent files
+#
+# Others
+RM      = /bin/rm -f
+#
+# Source, Executable, Includes, Library Defines
+EXE    = main
+#
+# Compiler, Linker Defines
+CC      = /usr/bin/gcc
+#
+all: main.o
+	$(CC) main.c -L/usr/lib/x86_64-linux-gnu -lconfig -Wall -o $(EXE)
+#
+main.o:
+	$(CC) -c main.c
+# Clean Up Objects, Exectuables, Dumps out of source directory
+clean:
+	$(RM) *.o $(EXE) *~

hello/readme.md

@@ -0,0 +1,23 @@
+* install dependencies on Debian Bullseye
+
+```
+sudo apt install libconfig-dev --no-install-recommends
+```
+
+* build
+
+```
+make clean all
+```
+
+* cleanup
+
+```
+make clean
+```
+
+* run
+
+```
+./main
+```