Embedded Linux for Developers

Using strace to show system calls

I started the chapter with the simple and ubiquitous tool, top, and I will finish with another: strace. It is a very simple tracer that captures system calls made by a program and, optionally, its children. You can use it to do the following:

• Learn which system calls a program makes.
• Find those system calls that fail together with the error code. I find this useful if a program fails to start but doesn't print an error message or if the message is too general. strace shows the failing syscall.
• Find which files a program opens.
• Find out what syscalls a running program is making, for example to see if it is stuck in a loop.

There are many more examples online, just search for strace tips and tricks. Everybody has their ...