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Top Forums UNIX for Dummies Questions & Answers Overhead of using a shared library Post 302424728 by Dongping84 on Wednesday 26th of May 2010 07:08:16 AM
Old 05-26-2010
The OS is ubuntu 9.10 and Linux kernel is Linux ubuntu 2.6.31-17-generic. The compiler I'm using is gcc version 4.4.1, the linker is GNU ld (GNU Binutils for Ubuntu) 2.20`and the dynamic loader is ld-2.10.1.so. I did not use lazy loading. The source codes are very simple.
The source code of executable is foo.c, it only calls bar1 of the shared library.
Code:
void main(){
       bar1();
       sleep(100);
}

The shared library only contains one object file (bar.o). The source code of bar.c is shown below. The reason I wrote so many functions was that I wanted to make the hash table and symbol table extremely large, because I thought that before any functions were called, these two tables should be loaded in the physical memory.
Code:
void bar1(){}
void bar2(){}
void bar3(){}
...
void bar20000(){}

The commands I used to compile and link are:
Code:
gcc -c bar.c
gcc -shared bar.o -o libnewshared.so
gcc -c foo.c
gcc foo.o ./libnewshared.so -o text

If you need any other information, please tell me. Thanks in advance!
 

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sdl-config(1)						      General Commands Manual						     sdl-config(1)

NAME
sdl-config - script to get information about the installed version of SDL SYNOPSIS
sdl-config [ --prefix= DIR] [ --exec-prefix= DIR] [ --version ] [ --libs | --library-libs | --plugin-libs ] [ --cflags ] DESCRIPTION
sdl-config is a tool that is used to configure and determine the compiler and linker flags that should be used to compile and link pro- grams, libraries, and plugins that use SDL. It is also used internally by the m4 macros that are included with SDL. OPTIONS
--cflags Print the compiler flags that are necessary to compile a program or library that uses SDL. --exec-prefix=DIR If specified, use DIR instead of the installation exec prefix that SDL was build with when computing the output for the --cflags, --libs, --library-libs, and --plugin-libs options. This option must be specified before any of the --cflags, --libs, --library- libs, and --plugin-libs options. --libs Print the linker flags that are necessary to link a program that uses SDL. --static-libs Print the linker flags that are necessary to statically link a program that uses SDL. --library-libs Print the linker flags that are necessary to link a library that uses SDL. (This excludes any static objects required for linking, since these must be linked only by executable programs.) --plugin-libs Print the linker flags that are necessary to link an SDL-using object that is to be accessed via dlopen(3). This may include static objects with PIC symbol information. This option should not be used for ordinary shared libraries or standalone applications. --prefix=DIR If specified, use PREFIX instead of the installation prefix that SDL was built with when computing the output for the --cflags, --libs, --library-libs, and --plugin-libs options. This option is also used for the exec prefix if --exec-prefix was not specified. This option must be specified before any of the --cflags, --libs, --library-libs, and --plugin-libs options. --version Prints the currently installed version of SDL on standard output. EXAMPLES
gcc -o main.o $(sdl-config --cflags) main.c is how you might use sdl-config to compile a C source file for an executable program. gcc -o my_app $(sdl-config --libs) main.o util.o is how you might use sdl-config to link compiled objects into an executable program. gcc -o libSDL_nifty-1.2.so.0.0.1 $(sdl --library-libs) read.o write.o munge.o is how you might use sdl-config to link compiled objects into a shared library. gcc -o libnifty_xmms.so $(sdl --plugin-libs) stream.o blit.o deinterlace.o is how you might use sdl-config to link compiled objects into a plugin for use by another program. AUTHOR
The Simple DirectMedia Layer (SDL) library was written by Sam Lantinga. This manual page was written by Branden Robinson, originally for Progeny Linux Systems, Inc., and the Debian Project. SDL 1.2 2001-12-25 sdl-config(1)
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