I got a program written in C and compiled with gcc, which I've tested for memory leaks etc in both Linux with Valgrind and in Windows with drmemory, and that with the relevant problematic argv arguments. I've found absolutely no problem doing so, and I get the output I expect when doing so. The only libraries included, and barely used are, stdio.h, stdlib.h, string.h, sys/time.h. Only output is printf and fopen to a specific file, which of course is closed after use, no messing with around with stdout or stderr or something like that.
I call this program from PHP with exec, and the program seems to work perfectly almost all the time, except for some few times when the executable takes like 30+ seconds or something along those lines. The problem is then that it seems I don't get the stdout that I should get assigned to the $output argument with the PHP exec function call, neither does it return anything, which should be the last line outputted from the program. The return value argument for the exec function gets set to 0, which really is the only return value the main function in the C program is set to return, there's no exit or anything else. I've of course set the time limit of the PHP script to 0, and it can run for hours just fine. Should also be noted I run this PHP script from cmd.exe in Windows 7 with administrator privileges.
I've been debugging this so much now, and before I decided to post here, I wanted to see if it actually got to the printf part of my program where the output I want should be printed, so I made it write the exact same string to file right after the printf. Guess what? It wrote the expected result to that file......
From this I take it that PHP exec somehow don't get the stdout output after a certain amount of time. Anyone got any ideas on how to fix this?
I guess a possible fix is to make the PHP script check the created file for the output instead of getting it through the $output argument that should get it from stdout. Perhaps do this when it gets nothing from $output, but this seems like a very shabby workaround.
Is there some kind of setting I've missed?
I'm running PHP 5.6.6.
EDIT: I've also already made sure to set this at the start of the PHP script before I even started doing any of the tests etc:
error_reporting(E_ALL);
set_time_limit(0);
