Parse /proc filesystem "files" for results

shlonginator · 12-01-2010, 12:42 PM

Hi All,

Im new to C so hope you can help.

Im reading in file /proc/cpuinfo into a char array.
Im using strstr to search for a string im interested in (the cpu speed line) and storing it in another char array.
I want to just store the line that contains CPU speed but im getting everything after the CPU speed line in the char array too.
Is there anything better than strstr or is there someway i can parse the the payload data (i.e. the actual cpu speed)

Thanks for the help,
shlonginator

grail · 12-01-2010, 06:00 PM

Well according to this definition:

Quote:

The strstr function locates the first occurrence of the string string1 in the string string2 and returns a pointer to the beginning of the first occurrence.

I am guessing you are searching for something like:

Code:

cpu MHz

As the definition says it will then return everything from 'cpu MHz' to the end of the string. SO maybe if you use strstr again but this time now look for the first
occurrence of a digit you will get what you are looking for.

If I have ballsed up what you are trying to do, then please let me know?

shlonginator · 12-02-2010, 08:09 AM

Hi grail.

Thanks for your response.
Yes I was searching for cpu MHz. There are other digits in /proc/cpuinfo so i cannot search with digits...
As you said strstr will return a pointer to the beginning of the first occurence.
However it also returns all the info after the clockspeed entry, e.g.

cpu MHz : 2133
cache size : xxx
physical id : x
etc etc

where I only want to store the cpu Mhz value.
Can you recommend anything better than strstr?

Many thanks,
shlonginator

grail · 12-02-2010, 08:16 AM

Maybe if you supply what code you have so far and we can work from there?
My C is rusty so it helps if I can see what we are trying to do

Guttorm · 12-02-2010, 08:19 AM

Hi

After you have found the position of "cpu MHZ" with strstr, you can look for the next newline. You get the length of the line with something like strcspn(line,"\n").