Answer: Yes, the position of the file pointer is updated automatically after the read operation, so that successive fread() functions read successive file records. Clarification: fread() is a block oriented function. The standard prototype is: size_t fread(void *ptr, size_t size, size_t limit, FILE *stream); The function reads from the stream pointed to by stream and … Read more
Here’s a big gotcha which confused me when I first tried connecting: the APNS feedback servers only return the device tokens that have “expired” since your last feedback request. Which means most of the time you’ll get a NULL response unless you’re already dealing with a high volume of users of your app. So make … Read more
Of course, that will not work as for strings it will copy the size of pointer, (usually 4 bytes). I see 3 options here: Serializing data, binary file (http://en.wikipedia.org/wiki/Serialization). Creating a format to store data in a text file. Use markup language like XML/JSON etc. In any case you would need to go through every … Read more
The simplest naive solution is simply: $file = “/path/to/file”; $data = file($file); $line = $data[count($data)-1]; Though, this WILL load the whole file into memory. Possibly a problem (or not). A better solution is this: $file = escapeshellarg($file); // for the security concious (should be everyone!) $line = `tail -n 1 $file`;
We can remove the null terminators on the command line using something like: sed ‘s/\\0//g’ mycsv.csv > mycsv.csv Or as suggested by @marbel, fread allows you to pass the sed call inside the text. Such as: fread(“sed ‘s/\\0//g’ mycsv.csv”)
There isn’t anything wrong with using the P/Invoke marshaller, it is not unsafe and you don’t have to use the unsafe keyword. Getting it wrong will just produce bad data. It can be a lot easier to use than explicitly writing the deserialization code, especially when the file contains strings. You can’t use BinaryReader.ReadString(), it … Read more
You may have undefined behavior, with the following scenario: int nbins; does not initialize nbins, so it contains junk data, potentially a very large number. fread(&nbins, sizeof(int), 1, fd); is not tested so could fail and keep nbins uninitialized. Read about fread. printf(“nbins = %d”, nbins); has no \n and is not followed by an … Read more
There may or may not be any difference in performance. There is a difference in semantics. fread(a, 1, 1000, stdin); attempts to read 1000 data elements, each of which is 1 byte long. fread(a, 1000, 1, stdin); attempts to read 1 data element which is 1000 bytes long. They’re different because fread() returns the number … Read more
You can try this: filelist = list.files(pattern = “.*.txt”) #assuming tab separated values with a header datalist = lapply(filelist, function(x)read.table(x, header=T)) #assuming the same header/columns for all files datafr = do.call(“rbind”, datalist)