Sams Teach Yourself PHP in 24 Hours, Third Edition

Running External Applications with passthru()

passthru() is similar to system() except that any output from the shell command you send is not buffered. This makes it suitable for running commands that produce binary as opposed to text data. passthru() accepts a shell command and an optional variable, which is filled with the return value of the command.

Let’s construct an example. We want to create a script that outputs images as thumbnails and that can be called from HTML or PHP pages. We are going to let external applications do all the work so that our script will be simple. Listing 21.7 shows the code that locates the image and outputs the data to the browser.

Listing 21.7. Using passthru() to Output Binary Data

1: <?php 2: if ( isset( ...