Compiling&Linking Error
 

Hello everyone,

I wrote a program that uses posix threads.i include header files to my project
and i compile with

gcc -c piThreads.c

that's ok i have a piThreads.o file but when i want to link this file with

gcc -o piThreads.o piThreads.c

i have an error like this :

/tmp/ccgNQ6AM.o(.text+0x14d): In function `main':
: undefined reference to `pthread_create'
/tmp/ccgNQ6AM.o(.text+0x15d): In function `main':
: undefined reference to `pthread_join'
collect2: ld returned 1 exit status

i included pthread.h file.

i tried to compile and link my project in redhat, it succesfully compile and link
also i have no problem at execution time...

when i look at pkgtool for libraries, i can see these libs for gcc

glib-1.2.10.i386-2
glib2-2.6.2-i486-1
glib2-2.3.4-i486-1

also i cannot add math.h library to my project too...

i really need help for this.

Thanx to all..

Did you try :
gcc -o piThreads.o piThreads.c -lpthread

And if you want math.h library:
gcc -o piThreads.o piThreads.c -lpthread -lm

yep, that's worked.

is there other parameters like (-lpthread, -lm ..) and how can i learn them?
and why am i need to add these?
i mean, isnt it enough to add .h ?


Thank you keefaz..

You need to add these to tell to the linker what shared library to link, eg

-lm : link math library to access math function
when you tell #include math.h, you just include the math functions definition, not the
math function code

You learn them by experience, there is not specific method to learn, just work
but for pthread, the lib is /usr/lib/libpthread.so and to link it you remove the 'lib' prefix
so -lpthread

Thanks.