lect10-debug1

Example
macro.c color.c
macro.c
#include <stdio.h> #define PRINT_ERROR(MSG) \ printf("Error [ %s : line %d in function:%s() ] \"%s\"\n", \ __FILE__, __LINE__, __func__, (MSG)) int main(int argc, char **argv){ int i = 0; // do something if (i == 0) PRINT_ERROR("i == 0"); return 0; }
Example
Can be used for debugging!
#include <stdio.h> #define DEBUG int main(int argc, char **argv){ #ifdef DEBUG printf("Something useful for debugging\n"); #endif return 0; }
Define Marco At Compile Time
#include <stdio.h> int main(int argc, char **argv){ #ifdef DEBUG printf("Debugging turned on\n"); #endif return 0; }
debug.c
Another Useful Macro
Macro to print integer, for example
#include <stdio.h> #define PRINT_INT(x) \ printf(#x " = %d\n", (x)); int main(int argc, char **argv){ int i = 123; // do something PRINT_INT(i); PRINT_INT(1+2); return 0; }
Example
macro3.c
#include <stdio.h> #define THIS_PROFESSOR_IS_GOOD int main(void){ #ifdef THIS_PROFESSOR_IS_GOOD printf("Is Good :) \n"); #else printf("Not Good :( \n"); #endif return 0; }
CO004 Projects on Operating Systems
Debug Basics
Outline
Predefined macros Useful macros Conditional Compilation
Predefined Macros
Try this!
printf("Line: %d\n", __LINE__); printf("File: %s\n", __FILE__); printf("Function: %s\n",__func__);
Conditional Compilation
Use #ifdef / #else / #endif Same set of code can be compiled to slightly different program For debugging For compiling into different version, according to different version of compiler/different target OS
Preprocessor replaces them into the corresponding value
More Macros
When you compile the program __DATE__ become the date __TIME__ become the time It is done by the preprocessor during compile time.
More About Color
\033[31;1m and \033[0m is a ANSI escape code 31 means “red” and 1 means “bold” 0 means “reset” Replace 31 with the following code to give Marco At Compile Time
#include <stdio.h> int main(int argc, char **argv){ #ifdef DEBUG printf("Debugging turned on\n"); #endif return 0; }
debug.c
color.c
#include <stdio.h> #define PRINT_ERROR_RED(MSG) \ printf("\033[31;1m" "Error [ %s : line %d in function:%s() ] \"%s\"\n" "\033[0m", \ __FILE__, __LINE__, __func__, (MSG)) int main(int argc, char **argv){ int i = 0; // do something if (i == 0) PRINT_ERROR_RED("i == 0"); return 0; }
Reference
/wiki/ANSI_escape_code /wiki/C_preprocessor /onlinedocs/cpp/Macros.html /~scs/cclass/notes/sx9.html Google