From afa331fdf3cff19500934e143aed226cfef097e4 Mon Sep 17 00:00:00 2001
From: Brandon Rodriguez <brodriguez8774@gmail.com>
Date: Tue, 20 Nov 2018 02:21:51 -0500
Subject: [PATCH] Create variadic macro spike
---
.gitignore | 1 +
spikes/variadic_macros/makefile | 3 ++
spikes/variadic_macros/readme.md | 5 +++
spikes/variadic_macros/variadic_macro.c | 30 +++++++++++++
spikes/variadic_macros/variadic_macro.h | 58 +++++++++++++++++++++++++
5 files changed, 97 insertions(+)
create mode 100644 spikes/variadic_macros/makefile
create mode 100644 spikes/variadic_macros/readme.md
create mode 100644 spikes/variadic_macros/variadic_macro.c
create mode 100644 spikes/variadic_macros/variadic_macro.h
diff --git a/.gitignore b/.gitignore
index 4cdb467..3dd39fe 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@ spikes/logging/log_with_macro
spikes/logging/log_file.txt
spikes/make/read_from_file
spikes/unit_testing/unit_tests
+spikes/variadic_macros/variadic_macro
# Ignore vscode files
.vscode
diff --git a/spikes/variadic_macros/makefile b/spikes/variadic_macros/makefile
new file mode 100644
index 0000000..7274de3
--- /dev/null
+++ b/spikes/variadic_macros/makefile
@@ -0,0 +1,3 @@
+
+all:
+ gcc -Wall -Wpedantic -std=c99 -g *.c -o variadic_macro -lcunit
diff --git a/spikes/variadic_macros/readme.md b/spikes/variadic_macros/readme.md
new file mode 100644
index 0000000..dadbaac
--- /dev/null
+++ b/spikes/variadic_macros/readme.md
@@ -0,0 +1,5 @@
+
+# C - Quadratic Solver > Spikes > Variadic Macros
+
+## Description
+Spikes to test use of variable length input for macros (variadic macros).
diff --git a/spikes/variadic_macros/variadic_macro.c b/spikes/variadic_macros/variadic_macro.c
new file mode 100644
index 0000000..e4edac1
--- /dev/null
+++ b/spikes/variadic_macros/variadic_macro.c
@@ -0,0 +1,30 @@
+/**
+ * CS 4900
+ * Variadic Macro spike.
+ */
+
+
+/**
+ * Description:
+ * Spike to test creating macros with dynamic number of passed args.
+ */
+
+
+// Import headers.
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "variadic_macro.h"
+
+
+
+/**
+ * Program's main.
+ * Initializes and runs program.
+ */
+int main(int argc, char* argv[]) {
+ va_printf("%s\n", "Hello world!");
+ va_printf("%s %s\n", "Hello", "world!");
+ va_printf("%s %d %d\n", "Nov", 20, 2018);
+ exit(0);
+}
diff --git a/spikes/variadic_macros/variadic_macro.h b/spikes/variadic_macros/variadic_macro.h
new file mode 100644
index 0000000..d02d6c0
--- /dev/null
+++ b/spikes/variadic_macros/variadic_macro.h
@@ -0,0 +1,58 @@
+/**
+ * CS 4900
+ * Header file for Variadic Macro spike.
+ */
+
+
+/**
+ * Description:
+ * Header file to hold variadic macro.
+ */
+
+
+// Import headers.
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+// Function Prototypes.
+void va_printf_func (const char *source_file_name,
+ int source_line_num,
+ const char *source_format_string,
+ ...);
+
+
+// Macro definition.
+#define va_printf(source_format_string, ...) \
+ va_printf_func (__FILE__, __LINE__, source_format_string, __VA_ARGS__)
+
+
+/**
+ * Function called by va_printf macro. Used for printing output of unknown length args.
+ * Notes:
+ * * It seems to just segfault if you use a bad/wrong format string specifier.
+ * Unlike normal printf, it will not give detailed warnings/errors about such.
+ * * Due to how va_list and va_start work, calling macro needs at least one variable defined.
+ * This variable is where the __VA_ARGS__ call will start looking for new args to handle.
+ */
+void va_printf_func(const char *source_file_name,
+ int source_line_num,
+ const char *source_format_string,
+ ...) {
+ // Create initial formatted string, with default formatting.
+ char* format_string = calloc(1024, sizeof(char*));
+ sprintf(format_string, "[%s %d] %s", source_file_name, source_line_num, source_format_string);
+
+ // Handle variable length arg input.
+ va_list va_arglist;
+ va_start(va_arglist, source_format_string);
+
+ // Format string with variable length values.
+ vprintf(format_string, va_arglist);
+
+ // Clean up.
+ va_end(va_arglist);
+ free(format_string);
+}
--
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