CODEWITHSUNDEEP
clinuxeclipsegccpthreads
Lucia
Lucia

Reputation: 371

Linking with shared libraries

I'm trying to compile and link some .c file. I have been using Eclipse IDE for C/C++ developers, and in my local machine i can compile without problems. However, when i try to compile and link the same file in a RedHat OS (gcc version is 4.9.2-6 in this OS) i'm having problems. I get some warnings at compile time, but those are fine, i think, i just ignored and the application still runs fine. Here are the commands i executed and the associated output:

gcc -O0 -g3 -Wall -c -fmessage-length=0 -std=c99 -MMD -MP -MF"example.d" -MT"example.d" -o "example.o" "example.c"

warning: suggest parentheses around assignment used as truth value [-Wparentheses]
warning: implicit declaration of function ‘wait’ [-Wimplicit-function-declaration]

This generates two files, example.d and example.o. Then, i try to link them, without luck, with the following command:

gcc -Xlinker -L/usr/lib -lrt -static -pthread example.o -o example
/usr/bin/ld: cannot find -lrt
/usr/bin/ld: cannot find -lpthread
/usr/bin/ld: cannot find -lc
collect2: error: ld returned 1 exit status

The commands are taken directly from the ones that Eclipse generates, and work just fine in my local computer (Ubuntu OS) but not in the RedHat environment. The last command didn't work, with and without the -L option. I suppose the directory in -L is fine, as i run, for example,

locate libpthread.so

And one of the locations i get is /usr/lib (also /usr/lib64, but neither work).

Any help will be greatly appreciated!! :)

Upvotes: 0

Views: 178

Answers (1)

Davislor
Davislor

Reputation: 15144

If you try to link a static executable, it will look for the *.a versions of the libraries, not what you usually want. Remove the -static flag. Or you can install the static libraries if you really want to. It also should not be necessary to add -L/usr/lib explicitly.

Upvotes: 2

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