Add a sample showcasing VA_OPT for logging

agagniere · Aug 18, 2024 · 682c1bb · 682c1bb
1 parent 058e62b
commit 682c1bb
Showing 1 changed file with 16 additions and 0 deletions.
diff --git a/book/samples/03_variadic_macro.c b/book/samples/03_variadic_macro.c
@@ -0,0 +1,16 @@
+#include <stdio.h> // printf
+
+#define MARKDOWN_HEADER "|Level|File|Function|Line|Message|\n|:-|:-|:-|-:|:-|\n"
+
+#define log_log(LEVEL, MESSAGE, ...) \
+	printf("|" LEVEL "|`" __FILE__ "`|`%s`|%i|" MESSAGE "\n", __func__, __LINE__ __VA_OPT__(,) __VA_ARGS__)
+
+#define log_debug(MESSAGE, ...) log_log("DEBUG", MESSAGE __VA_OPT__(,) __VA_ARGS__)
+#define log_error(MESSAGE, ...) log_log("ERROR", MESSAGE __VA_OPT__(,) __VA_ARGS__)
+
+int main(int ac, char** av)
+{
+	printf(MARKDOWN_HEADER);
+	log_debug("Hello world !");
+	log_error("Failed to open %s: %s", "bar.csv", "no such file");
+}