Advanced Programming in the UNIX Environment: Second Edition [Electronic resources] نسخه متنی

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.

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.

This provides a way to terminate the process when it tries to dereference a null pointer, a common C programming error.

The definitions are

typedef void     Exitfunc(void);
int atexit(Exitfunc *
func );

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.

The heap and the stack aren't allocated until a program is executed by one of the exec functions (described in Section 8.10).

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.

When shared libraries are not used, a large portion of the executable file is occupied by the standard I/O library.

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.