What's the use of .map files the linker produces?

A nice article on how to use map files for finding crashes.

http://www.codeproject.com/KB/debug/mapfile.aspx

Manually doing all this is very uninteresting.

I am not aware of any tools which can read map file and help in finding the crash location. If anybody knows please update us.

For embedded systems, map files are a lot more useful. (Although you wouldn't be using Visual C++ for that ;)

Things like knowing how close you are to running out of program/data memory, and what location a particular variable resides in, are important.

You need them rarely, but they can be handy debugging some problems because they give information on the location of functions and data.

For example:

• detailed information on all segments (code, data and other).
• link line numbers to code

You can use map files for debugging tools.

Linker maps can be very useful in large projects when you need to track dependencies between compilation units and libraries. Typically, a linker will report a symbol which caused problems, and more often than not, a simple search for this symbol name won't return any results (or will return tons of false positives for symbols like read).

Without a linker map, the only option you have is to analyze all available source files (after preprocessing pass if macros were used, which is typically the case) and hope that you find the relevant spot.

Linker maps usually have a section called "reference by file/symbol" which tells you which object file was required by another object file of your project, and which symbol exactly was referenced.

I was once working on a project which had to be ported on a system without locale support. The linker was reporting "undefined reference to _localeconv_r" errors, which would have been a pain to track down by searching through the sources. Luckily, a GCC linker map file generated with -Map=output.map revealed all problematic functions with a single search.