Pelles C forum

Pelles C => General discussions => Topic started by: neo313 on August 10, 2013, 05:27:05 PM

Title: Malloc thread safety in Pelles compiler
Post by: neo313 on August 10, 2013, 05:27:05 PM

I need to know if the malloc function( and family ) implemented in Pelles IDE is thread safe?

For example; the latest GNU C ( that would be glibc-2.17 ) has a malloc implemetation that IS thread safe.

I only know that Pelles is based on LCC compiler, but searching provided not much more information or source code.
Quote from main page:
>>The compiler is originally based on LCC (by Chris Fraser and David Hanson), but since then enhanced with support for C99 and C11, a global optimizer, a new register allocator, a function inliner, intrinsic functions, and many Microsoft C extensions.<<

Thank you

Title: Re: Malloc thread safety in Pelles compiler
Post by: frankie on August 11, 2013, 12:38:06 PM

The compiler is not relevant about the issue.
It depends on the crt and libraries if a function is thread safe or not.
PellesC was born from LCC, now it has been so deeply modified that doesn't remains a lot of original code. In short it is actually a completely different compiler from original LCC.
If you need the thread safe version of runtime you can select multithreaded library or DLL from the project options->compiler tab (or use directly the switches /MT or /MD on the compiler command line).
Alternatively you can link the MS runtime linking it to your code.

Title: Re: Malloc thread safety in Pelles compiler
Post by: liut on October 22, 2013, 07:49:54 AM

the most safe way is to use Win API (heap alloc and management functions) instead. I tested it in my multi-threads program with single-thread lib, no problem totally. If you use mulit-thread lib for linking, the program file size and performance would be a little bigger and lower, although it's not a key issue at the most time.
BTW never use some C functions with global varibles, such as printf/sprintf, most are in stdio.h.

Title: Re: Malloc thread safety in Pelles compiler
Post by: neo313 on October 24, 2013, 12:58:56 AM

Quote from: liut on October 22, 2013, 07:49:54 AM

the most safe way is to use Win API (heap alloc and management functions) instead. I tested it in my multi-threads program with single-thread lib, no problem totally. If you use mulit-thread lib for linking, the program file size and performance would be a little bigger and lower, although it's not a key issue at the most time.
BTW never use some C functions with global varibles, such as printf/sprintf, most are in stdio.h.

It is implementation defined. But all modern ones should be thread safe. I have found no problems with calling multiple printfs when testing.

I took a peek at the latest version of gnu c library and there is some mention of stream lock in there.