filename [ -readnow] [

option with any of the commands that load

-mapped ]

symbol table information, if you want to be sure

 

GDB has the entire symbol table available.

 

If memory-mapped files are available on your

 

system through the mmap system call, you can

 

use another option, `-mapped', to cause GDB to

 

write the symbols for your program into a

 

reusable file. Future GDB debugging sessions

 

map in symbol information from this auxiliary

 

symbol file (if the program has not changed),

 

rather than spending time reading the symbol

 

table from the executable program. Using the

 

`-mapped' option has the same effect as starting

 

GDB with the `-mapped' command-line option.

 

You can use both options together, to make sure

 

the auxiliary symbol file has all the symbol

 

information for your program.

 

The auxiliary symbol file for a program called

 

myprog is called myprog.syms. Once this file

 

exists (so long as it is newer than the

 

corresponding executable), GDB always attempts

 

to use it when you debug myprog; no special

 

options or commands are needed.

 

The `.syms' file is specific to the host machine

 

where you run GDB. It holds an exact image of

 

the internal GDB symbol table. It cannot be

 

shared across multiple host platforms.

core-file [ filename ]

Specify the whereabouts of a core dump file to

 

be used as the contents of memory.

 

Traditionally, core files contain only some parts

 

of the address space of the process that generated

 

them; GDB can access the executable file itself

 

for other parts.

 

core-file with no argument specifies that no core

 

file is to be used.

 

Note that the core file is ignored when your

 

program is actually running under GDB. So, if

 

you have been running your program and you

 

wish to debug a core file instead, you must kill

 

the subprocess in which the program is running.

12.1 Commands to specify files 127