BSS, etc..

Processes each comprise:

• "Text" (where executable binary task image resides)
• Data section (where initialized program data resides)
• BSS section (where uninitialized program data resides)
• Heap (where dynamic memory with malloc() and free() is allocated)
• Stack records user process; grows downward

+--------------------+
| "text" (bin. exe)  |
+--------------------+
| data               |
+--------------------+
| BSS                |
+--------------------+
|   .                |
|   .                |
|   .                |
+--------------------+
| stack              |
+--------------------+

Kinds of C language variables

• Automatic variables are pushed onto the stack when a function is called.
• Initialized variables are stored in the "data" segment.
• Uninitialized variables are stored in the BSS segment.

int  max_pix_val = 255;   /* goes in "data" segment */
int  pix_val;             /* goes in BSS segment */
main(argc,argv)
{
 int     width=640;       /* goes in "automatic" */
 int     height=480;      /* goes in "automatic" */
 int     m, n;            /* go in "automatic" */
 static  myNaN = 255;     /* goes in BSS */ 
}

Here's an example I found with www search on keywords: bss, test, stack, (Clemson University Fall 2001)

Assigned readings from the course textbook (man pages)

• ldd - list dynamic dependencies of executable files or shared objects
• ld - the GNU linker
• lint - C program verifier
• ar - create, modify, and extract from archives.
• ranlib - generate index to archive.
• nm - list symbols from object files
• objdump - display information from object files
• size - list section sizes and total size.