2012年7月21日 · _GNU_SOURCE is the only one you should ever define yourself. __USE_GNU is defined internally through a mechanism in features.h (which is included by all other glibc headers) when _GNU_SOURCE is defined, and possibly under other conditions. Defining or undefining __USE_GNU yourself will badly break the glibc headers.

A common approach is to conditionally #define identifier basename to different names, depending on whether _GNU_SOURCE is defined. For instance: #ifdef _GNU_SOURCE # define basename __basename_gnu #else # define basename __basename_nongnu #endif Now the library simply needs to provide both behaviors under those names.

2016年5月4日 · I now that defining _GNU_SOURCE can be used to enable the gnu extension, but now I don't want these extensions. I added -std=c++0x -pedantic , but _GNU_SOURCE is still define. The out put of g++ -v is as follows:

2017年11月29日 · Define it when you're using non-standard functions and macros. In your case, you're trying to use a non-standard function that is part of POSIX, that's why you need to #define _GNU_SOURCE 1. You want to get the full effect of _GNU_SOURCE but make the BSD definitions take precedence over the POSIX definitions, the use the _GNU_SOURCE. Check …

2011年7月28日 · Based on the GNU headers, I would say they're doing an implicit -D_GNU_SOURCE=1 which is why it thinks you're re-defining it to something else. The following snippet should tell you its value provided you haven't changed it.

2011年6月29日 · GNU make 3.81 and 3.82 produce Makefile:10: *** missing separator. Stop. which points to the dep2 call, dep1 is run without errors. The only difference between the two variants is the newlines in dep2 (and the whole point why I'd like to use define).

2017年5月3日 · I tried using -D_GNU_SOURCE when compiling but neither works, I am trying to use pthread_setaffinity_np and other mutithreading features but the compiler says it is out of scope. This is what I hav...

2015年3月19日 · The solution says, that I only have to include following: #define _GNU_SOURCE Which I tried, but as already stated, it doesn't work. I included it in following files: - grib_keys.c - config.h and tried to compile them with concurrent and not concurrent inclusion. In the end, the important parts of the files looked like this:

2012年1月12日 · The _GNU_SOURCE will most likely limits source code usage to GNU/Linux and GNU/Hurd systems, unless additional work is done to address the non-portability of such functionality on other platforms. Some companies, and government / military contracts may require certain platform standards to be used.

2017年1月3日 · These macros are defined by all GNU compilers that use the C preprocessor: C, C++, Objective-C and Fortran. Their values are the major version, minor version, and patch level of the compiler, as integer constants. For example, GCC 3.2.1 will define __GNUC__ to 3, __GNUC_MINOR__ to 2, and __GNUC_PATCHLEVEL__ to 1. These macros are also defined ...