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I want to know how malloc gets linked to the main program.Basically I have a program which uses several static and dynamic libraries.I am including all these in my makefile using option "-llibName1 -llibName2". The documentation of TCmalloc says that we can override our malloc simply by calling "LD_PRELOAD=/usr/lib64/libtcmalloc.so".I am not able to understand how tcamlloc gets called to the all these static and dynamic libraries.Also how does tcmalloc also gets linked to STL libraries and new/delete operations of C++? can anyone please give any insights on this.

pjain
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"LD_PRELOAD=/usr/lib64/libtcmalloc.so" directs the loader to use libtcmalloc.so before any other shared library when resolving symbols external to your program, and because libtcmalloc.so defines a symbol named "malloc", that is the verison your program will use.

If you omit the LD_PRELOAD line, glibc.so (or whatever C library you have on your system) will be the first shared library to define a symbol named "malloc".

Note also that if you link against a static library which defines a symbol named "malloc" (and uses proper arguments, etc), or another shared library is loaded that defines a symbol named "malloc", your program will attempt to use that version of malloc.

That's the general idea anyway; the actual goings-on is quite interesting and I will have to direct to you http://en.wikipedia.org/wiki/Dynamic_linker as a starting point for more information.

Mat
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