Section 1 - C and GDB review

C Review

static: has different meanings

• static functions indicate it can't be used outside of the file (like private)
• static variables are similar to other. ie only one

extern: declares variable without allocating any memory for it

• variables must be defined somewhere else
• allows you to use variables from other files

void change(char** s) { *c = "class"; }

int main() {
   char* s = "hello";
   char* w = s;

   change(&w);
}

When you use an uninitialized pointer, the address that the pointer stores is the uninitialized part, and will probably lead to errors when it is interpreted as an address.

GDB Review

printf debugging are useful, but limited when it comes to debugging concurrent code

Enter GDB

run <...args>: start execution

n: next instruction

bt: backtrace

watch <variable>: breakpoint when it changes

p <opt> <arg>: print arg

`x : dereference and print arg