I try to make a little program that sorts an array using threads but I can't get it to compile with the thread support.
Error:
sortieren.c:(.text+0xd7): undefined reference to `ptread_create'
I used a make file for easy compiling but also on command line I can't get it to work.
Basic code:
#include <pthread.h>
int main(int argc, char **argv) {
pthread_t threads[2];
// code snipped
int ret = ptread_create(&threads[0], NULL, threadOne(), NULL);
printf("ret: %d\n", ret);
// code snipped
}
Make file:
sortieren : sortieren.o
gcc sortieren.o
sortieren.o : sortieren.c
gcc -pthread -c sortieren.c
Using make sortieren
results in this output
gcc -pthread -c sortieren.c
gcc sortieren.o
sortieren.o: In function `main':
sortieren.c:(.text+0xd7): undefined reference to `ptread_create'
collect2: ld returned 1 exit status
make: *** [sortieren] Fehler 1
Of course I tried to google but every "solution" I found didn't worked for me. I tried -pthread
or -lpthread
everywhere in my make file. To be sure that I didn't do anything wrong in my code, I also tried a public sample:
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#define NUM_THREADS 5
void *PrintHello(void *threadid)
{
long tid;
tid = (long)threadid;
printf("Hello World! It's me, thread #%ld!\n", tid);
pthread_exit(NULL);
}
int main(int argc, char *argv[])
{
pthread_t threads[NUM_THREADS];
int rc;
long t;
for(t=0;t<NUM_THREADS;t++){
printf("In main: creating thread %ld\n", t);
rc = pthread_create(&threads[t], NULL, PrintHello, (void *)t);
if (rc){
printf("ERROR; return code from pthread_create() is %d\n", rc);
exit(-1);
}
}
pthread_exit(NULL);
}
The error is the same there.
System: Ubuntu 11.04 64bit, GCC-Version 4.5.2
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/x86_64-linux-gnu/gcc/x86_64-linux-gnu/4.5.2/lto-wrapper
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro 4.5.2-8ubuntu4' --with-bugurl=file:///usr/share/doc/gcc-4.5/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --program-suffix=-4.5 --enable-shared --enable-multiarch --with-multiarch-defaults=x86_64-linux-gnu --enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib/x86_64-linux-gnu --without-included-gettext --enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.5 --libdir=/usr/lib/x86_64-linux-gnu --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-plugin --enable-gold --enable-ld=default --with-plugin-ld=ld.gold --enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.5.2 (Ubuntu/Linaro 4.5.2-8ubuntu4)
Update
Using what @Banthar mentioned doesn't work, too.
$ make sortieren
gcc -c sortieren.c
gcc -lpthread sortieren.o
sortieren.o: In function `main':
sortieren.c:(.text+0xd7): undefined reference to `ptread_create'
collect2: ld returned 1 exit status
make: *** [sortieren] Fehler 1