Linux compilation errors and Solutions

1) as a beginner in Linux, I am only beginning to get started with thread programming. According to an example in the GUN/Linux programming guide, the following error occurs:

Undefined reference to 'pthread _ create'

Undefined reference to 'pthread _ join'

Cause:

The pthread library is not the default library in Linux. You must use the static library libpthread for connection. a, you need to link to this library when using pthread_create () to create a thread and calling the pthread_atfork () function to create a fork handler.

Solution:

Add the-lpthread parameter to the compilation.

Gcc-o thread. c-lpthread

Thread. c is your source file. Do not forget to add the header file # include <pthread. h>

2) Warning: Implicit declaration of incompatible built-in function strlen and implicit declaration of incompatible built-in function exit

Cause: the strlen function is in string and the exit function is in stdlib. The header files string. h and stdlib are not added to the file.

Solution: add the header files string. h and stdlib to the file.

3) error: Unknown storage size of sem_union

Cause: in the new version 2.6 kernel, the union sem_union consortium has been commented out, and you need to write the consortium yourself.

Solution: define in file C

Union semun {int val; struct semid_ds * buf; unsigned short * array;} sem_union;

After compilation, it will be able to find the pre-defined sem_union consortium.