| 7.1 | It appears that the return value from printf (the number of characters output) becomes the return value of main. Not all systems exhibit this property. |
| 7.2 | When the program is run interactively, standard output is usually line buffered, so the actual output occurs when each newline is output. If standard output were directed to a file, however, it would probably be fully buffered, and the actual output wouldn't occur until the standard I/O cleanup is performed. |
| 7.3 | On most UNIX systems, there is no way to do this. Copies of argc and argv are not kept in global variables like environ is. |
| 7.4 | This provides a way to terminate the process when it tries to dereference a null pointer, a common C programming error. |
| 7.5 | The definitions are
typedef void Exitfunc(void);
int atexit(Exitfunc *func);
|
| 7.6 | calloc initializes the memory that it allocates to all zero bits. ISO C does not guarantee that this is the same as either a floating-point 0 or a null pointer. |
| 7.7 | The heap and the stack aren't allocated until a program is executed by one of the exec functions (described in Section 8.10). |
| 7.8 | The executable file (a.out) contains symbol table information that can be helpful in debugging a core file. To remove this information, the strip(1) command is used. Stripping the two a.out files reduces their size to 381,976 and 2,912 bytes. |
| 7.9 | When shared libraries are not used, a large portion of the executable file is occupied by the standard I/O library. |
| 7.10 | The code is incorrect, since it references the automatic integer val through a pointer after the automatic variable is no longer in existence. Automatic variables declared after the left brace that starts a compound statement disappear after the matching right brace. |
