Question

#include <stdio.h>

int main(int argc, char* argv[]){
  printf("argc: %d\n",argc);
  for(int i=0;i<sizeof(argv);i++){
    printf("argv[%d] %s\n",i,argv[i]);
  }
  return(0);
}

compiles fine, when using it under a gnome terminal under a GNU/linux distribution

printTest one\ two three
argc: 3
argv[0] /data/local/tmp/printTest
argv[1] one two
argv[2] three
argv[3] (null)

I intentionally left a white space escaped and argv seems to behave really strangely.

Is this behaviour normal ? What is that null ? why argv creates a null pointer instead of just providing a shorter array ?

Answer 1

sizeof(argv) is meaningless — it’s the size of a pointer (4 on your platform), which just coincidentally happens to be one more than the number of values in argv in this case.

Use argc here instead.