C Programming: Understanding Variable Declaration and Initialization with popen() and fread()

This code snippet shows a variable declaration and initialization. \u000a\u000aThe line `FILE r = popen(msg.cmd, "r");` declares a pointer variable `r` of type `FILE`. It is being initialized with the return value of the `popen` function, which opens a pipe to a command specified by `msg.cmd`. \u000a\u000aThe subsequent line `fread(msg.data, sizeof(msg.data), 1, r);` reads data from the file stream `r` and stores it in the array `msg.data`. The `sizeof(msg.data)` specifies the size of each element to be read, `1` specifies the number of elements to be read, and `r` represents the file stream to read from.