1

I use use ip by system("ip link set eth0 up") in a C program. I know that system returns -1 if it fails and returns what the called function returns(exit). E.g., if eth0 is not exist on the system, it returns 256. Where can I find what these numerical values defined for ip?

For example ifconfig's Return Codes:

Return Code Description
0    The command completed successfully.
4    The command completed successfully, but a warning condition was detected.
8    The command was not specified correctly.
12    An error was encountered.
16    An unexpected condition was encountered.
Improve this question

2 Answers 2

Reset to default
3

According to the man 8 ip next exit codes of ip exists:

Exit status:

0 = success

1 = syntax error

2 = kernel error

Improve this answer
2

You'll find the return values in the documentation. Failing that, look at the source code.

I think ip doesn't do anything fancier than return 0 for success and 255 for failure.

Make sure you've read the documentation of the system function properly. Your description is wrong: system only returns -1 if it fails to start the external program, otherwise it returns a value that encodes the process's return code and other information. 256 means that the process returned 1.

Improve this answer
0

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.