System function always returning -1 even though curl command success in C

Question

0.00/5 (No votes)

See more:

I am working in router development which is Ubuntu machine. In my code im trying to execute a curl command using system function but the system always returning -1 even though curl command got success. I observed this issue coming when my router wan ip changed. I see for any curl command in this case, system returning -1.

Could you please help me how to solve this?

What I have tried:

ret = system("curl --url myURL --trace-ascii /tmp/log.trace >/dev/null 2>&1")

if(ret == -1)
printf("system failed.....\n");

but my trace file contains 200 successful

Posted 23-Feb-22 19:28pm

Member 13740197

Updated 23-Feb-22 22:24pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard MacCutchan · Accepted Answer · 2022-02-23T22:24:00

Solution 1

A return value of -1 indicates that the exit status of the curl command could not be captured. See system(3) - Linux manual page[^] for full details.

Posted 23-Feb-22 22:24pm

Richard MacCutchan

Comments

Member 13740197 24-Feb-22 8:57am

Thanks for the reply Richard.
I have checked the man page and found below one to get exit status.
WEXITSTATUS(ret);
But in my case it is getting 255, how can we find root cause, based on this value?

Richard MacCutchan 24-Feb-22 9:21am

255 is the same as -1. But I really do not know what you are doing.